



V'-VT* - v 






(■A A) ’’’j • ' d h O t.'~££iM'^'■)* „0 »i> './'‘"''i^S 3 ^ « C . 1 -_ 

0 v .. v ^ *"’* *'%'• % &0N ° S >yo,\ "' 

/ :m\ %■/ \/ :Ste: V" •&& V* i 

A ■* >=3MMP^P ° ,A **> o 1 

.? ^ » §£7lw\X * 4 V 0 ^’ '^* °* l/ ^"^ V -* ^_ v V ^* - 1 

><A ^ '*'“ ‘'° V”w/ 


O 


V. 


V> *'V. •* V 

A > 


+ *o< 


0 0 ^ 0 - * /^ i ^ 1 

0 -r-CSiv *- . ■> i*fr 

“ d-s^ki- J .♦ 


O ..' 


A 

,0r 0 0 « 0 , 


if * <0 * 7 * * ^ 

v „ * **. v 


'0 A ^ s 

' y o_ v 


c *° -v - 

-V A it» 


« 


« 0 ' A' '^b. 

V v * ’ * °* C- <v 

AV ♦ j{\gf 4 0 A 1 

.^V • Jx\%sk//h, o 'Vrv CP o 


,, 1 * A° V. 

<<y **vl% *> 






0 ’ \ 

V^ .••- V A .LV 1 '. " 

* ■•■*■•• 4, ./ •*■ 


4o V 


^^onO 0 .V' ^ 

A 0 y * °- c\ <0 ^,/w * 

k a ,V\Va % ♦<* <£* ^ ^ * 

:§MWh\ :jO||: v-a * 

' *' A^ *5> “o'VJilAF * ^ ^ 

o */77;V A <, **».»*'* (P ^ A <?> '«•»* a G ^ ‘‘''•* $4 "°*‘ • 

u I « ’<$> fO^ «• 0 w 0 -» jV , I. " ^ ^ -0^ C° N0 '» C)^ A.^ t • ** ^f> f 0 

L ‘ * - * *- c o ,V^ %. c 0 <v *&((!???^-> « 




'o A ^ 
" to 


«5°a 


Y///&s}^SSi o ,-4 vP ^ 

m/ c 8 \n 4 -C^ ^ 

- 0 . 4 * ,G V ^» '7. * 4 

A V o N o # '^4 > 


vV’ W7 \‘^v' v^/ ‘V---V' ^'-... „ 

A . , 'V- " V ^>V s . . . \ v , . o S • • / V* V v * 1 * °- 

<v vL^f-vO* ^ V » ’ “•» C\ a*' Oww* ^ . , v ^ f & 5,'. A ,a <.. ► 

A V «. A ♦ jaW/jT** ^ •VSIfef • ^ * A sf A° "vn * ^iilS * ^ * 

0 JiBi: vv :mmm\ vv ^ 

O- * - A v/' -* %^liDini ^^ 0 A v -4. O * A VV> -“ 0 

^V 0 -y^^^4 ZjV' '0 > ^ ^ <4 -OLA -»^ X ^ ^ . 

<!4 ' 0 . 4 * Jr ^ V7a 5 A ^ ' 0 . 4 * jy o ^..* 4 A ^ ~ 0, ‘' A n 0 *f» 

,. <f> i n« t< -t <iS ,t «. 4 o° wo - ^o A .'■'*-» ^ r o v C»A% O n 

^ r U . C _T"CV\ % > 2 .*»• t fyfyrj ^ ■'r Cj O j 10, j ?*>/r???-.^ , -?■ v _ •jeSSaYVv'^. j. ^ -N 

^ :tfff^’ W :^K- : Wk': I s -^R: "A 

. '^n ^ r*^ . d 0 „ • 4 O v\ * 0 A dP 

.-wA -o.‘^*/ %'^-y -* 

aO^ ,L!oL^ ^ V ^V' 0 -, C' <0 ^ s 





■A V V . ^ . 

«■ A <*• "o. k * 



N <J 


■» + C \0 rf* •» '^3>J _ 0 * 4 

«° v V Ki, '•*'• “*° f -<u ' " *r 

V s •*•«»- O. aO ^ V % k A*°' aO v * 

'/ %A V,V -'hsmz ^ 

v \ : -W- ; v v A ; .®* /\ -®“ A A 'WW/\'- 

%,, *A.^* A <.'»•»* A *>..«' A 4 , •• 4° 

,, ^‘ v ^ t f « ^ QV c 0 N 0 -9 ^o Av y 0 L 1 e 4 ( 

1 *^ + % L>A?9Z+ ^ C U ° ^ * % &(fl7fct?* Ta ^ ^ w 4 J 

^ - =v^i» ^ A +*<$ ^ov . 

a p ^ **‘rrr-*'.o-' V'-^'A 

N < y > v # s • • , ov A v , . 0 s s • • f& V v * y *« 

A ^ A /aV^v ^ c^ *v$ltv. ^ aV 

^ A ^\W/>L„ 0 

*.; a 7 v. 

*■ V^. 


0? o 0^ i 5 **' ^4> V %v e »*o, ' 7 o 

4 '^* ■**■"*' > n A*' VgffgV* ^ ’ 

’^ v :^i^°. ^ ^ * 

6 ^ J .«S^ 4 ° A^ V ^ °iW,* °c> J -18v*° A.^ V ^ O 

* > ^ w ,V V, -» A V •'?.?•* . 0 *- V**.r.'.‘ v 

0 ^ c»“° % ^o ^ ,-A^ ^ 



V ^ 

feJ “ °o ^ 



; ^° ^ ’ w > 

- # ^ ■* 

I/O A* <P^. ® N V 

a 0 s s V '4 4> v V * v *°- c> aV' *• 

.* ‘4*ttO ^ A AWA v ,0 .‘-* 

A AX “ /K Xi'% % • 




10 <t»' 

' to 





* ^ ^9 •* A 


?* ; /’V-^* ; v v A °®S- ; /'\ : -|K* : y\^W* ; ^ 

*6^ V A <^ '••»* aCV ^ 4-t^ s , a ^ „ 0#k * 

r\^ o w o <v u # b ^>w Qr r, 0 N 0 + 0 L 7 ® *> -*0 





- °o d*^ , 

k 0 ' AV k 

*&. in ^ ^ CV K 

* dO ~‘ 

r o dj> 

-^. '”■» O * 

A- ^ 4 ' 0n ° ^ 

) O’V'* ^ V ,'*»« C\ . 

^ A *>V/kV ■V n A 

v^' ; $m/A ° - gg; 0-0 •“• 

AA -.IMS': 

\5 A V> ' , ' 0 • * <Cr --o.s^ A ^ 

N O „ V ^-J . l 1 « ■d^ 0^ . 0 « O ^ .A « 1 ' 8 <1 ^ 

°o ,A t „/v 4 j, 4 ’f G •VrSSXv^ O d^ Sce/r??^ ■> v, 

•SJ,)* .'ilSfllV- -^O* ' J o I-**’ '^■d® 

: o°- ‘■°^- ’.mfeK.- a°. 



0 c 


■k. .-Vl\w° 

^°° V** ,, ‘/ 0< v 

Ap V **^4, V V 





• <-' ^ • ^ea p?^cS/“ v • ^(TJ g|>^ * ? ^ * C® F^V * 

a a°xv k <a vp 

\%/ %»*/ V*-/ V‘ 

yy % ** m r+ ^ $ * ito * v ^V ^ ”^ V 

^A /\ l^s*“ AA ^^R* ; /\ A A /% \ 

' ‘■—’A ..../V’’** o^.»*-.°V'‘*‘‘A .‘-AV'“V° 

* ‘-^* - c v«'. ° 


* A 'A 

* v < V> 

*' & v' * .^y 

<. 'o. *• «G o, ”•' 0. s - a 

t'» ^ 0 ^ 0 0 N 0 ■» **b A 

■*£ G • o iA * w &>si 775 *, ▼ w 

■%o® ••-^te: ’•A* ^ 0 ® 

; jP-^ : 

vO ^ 4 

<?> ° N 0 A 


<^°4* 


,1 wxsna >1 tO _ ~zsy/ivA& * t\ ' * 

<t.p cv * A 

0 o» O *0 

0 « 0 A <^K * ' 1 A 

* > - 1 • O <r\ .r» v - s 0 * r . 



A°* 


. a°<. ~f3%gi- s- 0 ^ -< 

' _ ^Vv/V£> * A •- £ * ,l> -.-MVW 

<j_r O * ^-CiAf^y ') '« %.* - -w* •» p.. 

^ %> * * » 1 * A 0 V* * • • 0 <V * ' ' * A° 

<? ,<y V> A Vp. 4 O 


'• J?- ”0 * 


\V *p. 

KS • 1 *o„ O 







4 d- o .v«* a 

»v , c v \^sw* ° sy * 

*■>- o' ;«2iia: ■’b# ' 


* V 


* .^'V y* 

<x 'o.A .0* V5 *77',* A ^ 

qV & 0 n C ^ ^ 0 © t 7 9 ^ 

,M A A" *•"■’ A A 

o. ,9‘ ,•••'. -- V . •••- c\ ,0 ,*••'. > \> ..• 

^A ^ a, A 1 . Ay '<• a 

5 * %<* AV *fCC\««/h,° ^ ej* * 

- ; vv ! §MrWk * ° 

* <-4 u\ -■ o a V o yy/yri 

* «? '■Qcx ©ii^ * aV ^ o 

^ v * ~ ^ ^ ~ ***Hfw0v \ ^ ^ ^ ^ - ^-> 

*'/. s' A <* *<>. i* <(y \s *v / 0 S * A <> *° • * * ^ 

# L * ^ Q * c ° N G + ^Q ^ # L I B ^ ^jj 0 ° N C « *(3 

w ,v ^’- ^ :42@&* ’W ■^^te'-. %v^ .' 

; *p*n^ vSSiS^ «*°* r'^zmS: aP^ 

A* '-'. 

(.v *£« 

-A • °x ^ A 

*o V /» *’*S 

vo v* ■ M* 



o 4 °y* ^ // „^ , 

^ o v<^* _o ' ^ *> c\ O o 

°- 41 * - 1 • f° «> ‘ s »° f ^ ' 1 * f° .. 

: %./ .7«A". ' 

‘ ■'""* * c,^ 

* / 




° -a. yo ~<^yyy/i\ i.i^ ■* ^ '^v 

x* «• w>\in\\y ’ \ y _ > /-\ /u — ^-hiwvj 

* ° » 0 ’ 0 Wx * S 1 1 * ^ 0 ^Vx *" 0 « 0 V?> v ^ v 

*V^ ^y> V C\ » 0 V i>V% ^ V % <‘ , *°- C\x a 0 ^ V « 

k • (V «■ Ar ° -<^ A o v >V Vv ♦ jA/}i, 0 ^rv * t 

'§mM 0 “MSm' ^*v 4w; °^fS^- v-sr 

”^S*' /\ ; -.w* ^ : *^K* /\ •.?»?.• 

/.-. v°“‘ o* 6 .—.\”^ ..... V”‘> .—. V” / 

c > '^' v '' :isi^’ ^ •: 

n • i. 0 ^. : 

o J 

.o ; ^ 




tQ ^ " * • 7 ' ■' „b° 

< * ° . CV «0 X 5 

,« *P. Ay 

h.° ^rv c,^ ■* 

* ‘ °o* 9 S « 


«Jx ^ 

^ * « « 0 0 ^ 


*^v!s* A O • 

*bf *W f 

o ^ _ 


.° A c. ‘-w,* n o ‘ '-*. *. 

X V^x " " - A y^x ® ' 1 A - " \y 

y> v x p ’ ” CK ST A>° % > V ** 

.\.,^ ,(? ^ y x ‘. 0|( / A- ^ 

^ ,o^ o^ ° % ^°-> A^ t'"!!- ^ c° °o 


^ °4- 

A *aWaa ^ 


A u 

x0 v o°JL°% "o 
C /^Sh'C* ^ A 


r * A v ^ 

; 4 A <^. '° * A 


-' o *ZW*f o 0 -V - 

•% "> V N A*^ a0^ ^ 

<f> *V ^ V ^X 5) • ^ ». ^ ^ 4 

»■' w : Mm°, a/ •• 



,V ^ ^ rf'\il\v\w h k > * ^y// pgr ♦ r\ -i* * 

'° ^ " > * ® » 0 5 °°^ * 8 ' 1 * ’ f° ^ * ° » u ^ 

^ V N A * ». <T\ A V A VL% *> V % * 

'*“’• °'Msk\ W .-, 

A A j . 

y ■*■.. 


' & <b 

\ yy * 

'": /\ /\ b^E* : y*+ °W!P. fV 

^ ... -a -•‘* „A... V^-'A ... v /.-.^ 

/ Vx x C 0 



^ X5^'y r A’^' *«■ 

« • O, ^ <0^ AV'^. > V % A*®- C\ 

V : %/ :#• **-£ •. 

_ •“ y y *y a yvJyJ' <y“ y yyfhfr' y 
*?7^ A <V *'°. a' o ^..s 4 A <> 

A> . i / «^ <P 0 V c° N ° ^ o A . >• ' * * 

> y^/r??^, * v c . ° sne/ftTpy t. 7. ^ 

A A* O' 





0^ ^ Aa a 

qV o N G 4 ^O A^ a L 1 ® ^ 

- ° %,/ :f^- 

» 5 -A A : .^R.* ,»° ^ *3a^. ; / ’’ym*: o 40 A '-'. 

s*» x A> A ,' * 0 , c>. <0 ^ V »!,*"' A, 4 P ^ 4 

7 \ ^ %> j ? 3 °^v ^ °vX^* y °^- 

*'?**'<? ^ <,*'»* A ^ % A ..A A <U'**** 

1 0 ^ G 0 " 0 ♦ **b A 1 ' * ■» ^ . 6 ^ G 0 " 0 A5 ^ A 1 '* ^ 0° V » c 

C •%5Av^y. ^ * WA/'biA x 7, . ^ ^ A * rJ Vx x v 

+x n f °v§|S^*. ,y b^ :£mj£p* ^o 4 :Mf|a* '*'?'• «i 

\'b^-' A A'^a/ __ A‘* 

$ # • /■ ,< ^> « y * °x- o <0 % 5 /w'4. ^ V p ^' °' c\ 

iV:. ♦ ^ ^ P x-j o. J-ii . *rV t «p jv y. >■ . 


A o * > 4 o 0 v 

^ o, ** 11 * a° y 

a* ox . 0 ^ a * •'. ^ 
















Serial No. 50 


DEPARTMENT OE COMMERCE 

U. S. COAST AND GEODETIC SURVEY 

M 

E. LESTER JONES, Superintendent 


geodesy 


INVESTIGATIONS OF GRAVITY AND ISOSTASY 


BY 

WILLIAM BOWIE 
CRief of Division of Geodesy 
LI. S. Coast and. Greocletio Survey 


SPECIAL PUBLICATION No. 40 



WASHINGTON 

GOVERNMENT PRINTING OFFICE 
191 ? 












ADDITIONAL COPIES 
OP THIS PUBLICATION MAY BE PROCURED FROM 
THE SUPERINTENDENT OF DOCUMENTS 
GOVERNMENT PRINTING OFFICE 
■WASHINGTON, D. C.’ 

AT 

60 CENTS PER COPY 


D. of D. 

FEB 23 191T 


CONTENTS. 


\ 

>» 

K 


Page. 


Introduction. 5 

Part I.—Investigation of Gravity and Isostasy. 

Chapter I.—Definition of terms and explanation of methods of computation. 7 

Isostasy defined. 7 

Assumptions made in regard to the topography and isostatic compensation. 8 

Change of sign due to distance. 8 

Reduction tables for effect of topography and isostatic compensation. 9 

Corrections and additions to tables. 9 

Chapter II.—Corrections for topography and isostatic compensation and principal facts for gravity stations_ 19 

Mean elevations and corrections for topography and isostatic compensation for separate zones at stations in 

the United States. 19 

Mean elevations and corrections for topography and isostatic compensation for separate zones at selected 

stations in Europe. 45 

Principal facts for 219 stations in the United States. 48 

Principal facts for 42 stations in Canada. 54 

Principal facts for 73 stations in India. 55 

Principal facts for 40 stations not in the United States proper, Canada, or India. 57 

Chapter III.—Comparison of apparent anomalies at stations in the United States by the Hayford and old methods 

of reduction. 58 

Gravity anomaly maps. 61 

Agreement as to positive and negative areas deduced from gravity and from deflection data. 62 

Chapter IV.—Relation between the gravity anomalies and the topography. 63 

Chapter V.—Relation between the gravity anomalies and the geologic formation. 70 

Relation between the gravity anomalies and the geologic formation for stations in the United States. 71 

Relation between the gravity anomalies and the geologic formation at stations in the United States not 

within 20 miles of another formation. 78 

Relation between the gravity anomalies and the geologic formation for stations in Canada. 80 

Relation between the gravity anomalies and the geologic formation for stations in India. 81 

Relation between the gravity anomalies and the geologic formation shown graphically. 82 

Relation between the gravity anomalies and areas of erosion and deposition. 84 

Chapter VI.—Regional versus local distribution of compensation. 85 

Relation of local compensation anomalies and regional compensation anomalies to the topography. 88 

Chapter VII.—Effect of the elevation of the station upon the intensity of gravity. 93 

Chapter VIII.—Effect on the intensity of gravity of changes in the depth of compensation. 97 

Gravity anomalies for various depths of compensation for stations in the United States. 103 

Relation between the depth of compensation and the topography. 107 

Graphic determination of the most probable depth of compensation. Ill 

Constants for the gravity formulas and the most probable depths of compensation derived by analytical 

methods from gravity data. 113 

Helmert’s depth of compensation from gravity observations. 131 

Chapter IX.—Summary. 133 

Bibliography. 135 

Part II.—Summaries of Gravity Observations and Descriptions of Stations. 

Chapter I.—Abstracts of results. 139 

Chapter II.—Descriptions of stations. 177 

Index to publications containing abstracts of results and descriptions of stations. 187 

A1 phabetical index. 193 


3 










































4 


ILLUSTRATIONS. 


ILLUSTRATIONS. 

Fig. Page. 

1. Original form of the Mendenhall half-second pendulum apparatus. 48 

2. Mendenhall half-second pendulums as originally constructed with knife edge attached to head of pendulum 

and divided into two parts. 48 

3. Present pendulum apparatus showing vertical form of telescope, electric illumination for observing slit and 

the felt-and-leather case for controlling the temperature. 48 

4. Felt-and-leather case for temperature control partly removed from pendulum receiver. 48 

5. Graphic determination of the most probable depth of compensation from 216 stations in the United States.. 110 

6. Graphic determination of the most probable depth of compensation from United States stations east of the 

ninety-eighth meridian. 110 

7. Graphic determination of the most probable depth of compensation from United States stations west of the 

ninety-eighth meridian. 110 

8. Graphic determination of the most probable depth of compensation from 56 United States stations in moun¬ 

tainous regions. 112 

9. Graphic determination of the most probable depth of compensation from 20 United States stations in moun¬ 

tainous regions and above the general level. 112 

10. Map showing location of gravity stations in the United States and Canada used in this investigation_In pocket 

11. Lines of equal anomaly in the United States and southern Canada for the Hayford 1912 method of reduction 

(depth of compensation, 113.7 km.). In pocket 

12. Lines of equal anomaly in the United States for the Hayford 1916 method of reduction (depth of compensa¬ 

tion, 60 km.). In pocket 

13. Lines of equal anomaly in the United States for the Bouguer method of reduction. In pocket 

14. Lines of equal anomaly in the United States for the free air method of reduction. In pocket 

15. Enlarged scale for the region surrounding Washington, D. C., showing lines of equal anomaly for the Hayford 

1912 method of reduction (depth of compensation, 113.7 km.). In pocket 

16. Enlarged scale for the region surrounding Washington, D. C., showing lines of equal anomaly for the Hayford 

1916 method of reduction (depth of compensation, 60 km.). In pocket 

17. Geologic formations in the United States east of the Rocky Mountains. In pocket 

18. Illustration from Supplementary Investigation in 1909 of the Figure of the Earth and Isostasy, showing 

residuals of Solution H, all stations, with areas of excessive and defective density, and showing also all 
gravity stations and the Hayford 1912 anomalies. In pocket 


















INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


By William Bowie, Chief of the Division of Geodesy. 


INTRODUCTION. 

For a number of years the United States Coast and Geodetic Survey has been carrying on 
geodetic investigations of isostasy, with special reference to the effect of the isostatic compen¬ 
sation upon the deflection of the vertical and the intensity of gravity. 

Four reports on these investigations have appeared, the first one in 1909 and the last in 1912.® 

The first two dealt with the determination of the figure of the earth from deflections of the 
vertical in the United States, corrected for topography and isostatic compensation. In the 
last two there were given the results of the investigation of the effect of topography and isostatic 
compensation upon the intensity of gravity at stations mostly in the United States. 

The present volume gives the results of further study of the relation between gravity and 
isostasy. In it are embodied the gravity data resulting from the previous work. In the second 
gravity report 124 stations in the United States were considered, while in the investigation of 
which this volume is a report there are listed 219 gravity stations in the United States, 42 
stations in Canada, 73 stations in India, and 40 others, principally in Europe. The Canadian 
stations were established by F. A. McDiarmid, of the Geodetic Survey of Canada. He reduced 
those stations for topography and isostatic compensation after the method described in Special 
Publication No. 10. The late director of the Geodetic Survey of Canada, Dr. W. F. King, gener¬ 
ously furnished to the United States Coast and Geodetic Survey the results of their work for 
incorporation with the United States stations in some phases of this investigation, previous to 
their publication in Canada. 

This report has as its main features: 

1. The observed value of the intensity of gravity at stations in the United States, Canada, 
India, and Europe and at a few scattering stations. 

2. Discussions of the Relations between the gravity anomalies and the topography, the large 
areas of erosion and deposition, the geological formation as indicated by the surface rock at 
the stations, and the elevation of the station. 

3 . The regional versus the local distribution of isostatic compensation. 

4 . The determination of a gravity equation, the earth’s flattening, and the depth of com¬ 
pensation upon each of several assumptions. 

5 . Summaries of the results of the field observations with the pendulums. These furnish 
a basis upon which to judge the accuracy of the determination of the intensity of gravity at 
the various stations. 

6 . The illustrations in the pocket at the back of the volume, which give graphically much 
data resulting from this investigation. 

There are other lines along which investigations might have been made. Some of these 
may be undertaken at a later date as more data become available. One of these is the detailed 
study of certain regions where there are gravity and deflection stations and where the evidence 

a Figure of the Earth and Isostasy from Measurements in the United States, by J. F. Hayford, 1909; Supplementary Investigation in 1909 
of the Figure of the Earth and Isostasy, by J. F. Hayford, 1910; Effect of Topography and Isostatic Compensation upon the Intensity of Gravity, 
by J. F. Hayford and William Bowie (Special Publication No. 10), 1912; same title, second paper, by William Bowie (Special Publication No. 12), 
1912. 


5 






U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


6 • 

points to strong local disturbances or causes which change the size and sign of the gravity 
anomalies at stations grouped comparatively close together. This phase of the subject is an 
important one and has been urged upon the Survey by several scientists of note. 

It is hoped that many of those who are interested in the subject of isostasy will use the 
data contained in this and similar publications of the Survey for detailed study and investigation. 
It is only in this way that the data collected and published can be fully utilized. The time 
which can be placed on this work by members of the Survey is necessarily limited, because of 
many other lines of duty calling for prompt attention. 

It is believed that it is desirable to publish promptly the observed values of the 
intensity of gravity and the reductions for topography and isostatic compensation rather than 
to delay for exhaustive detailed studies. 

The author desires to express his appreciation of the important part taken by a number 
of the members of the Survey in the investigations covered by this report and in the preparation 
of the report itself. Especial credit is due Computers W. D. Lambert, Sarah Beall, H. G. 
Avers, C. H. Swick, E. F. Church, and G. E. Selby. 

Assistants C. L. Garner and J. D. Powell deserve much credit for the efficient way in 
which they carried on the field work while establishing the 94 new stations. They did this work 
with great accuracy and economy. They also assisted in the office reductions. 

As far as possible this report follows the general plan of the two previous gravity reports 
of the Survey. As the writer is the author of the second of those reports and a joint author 
of the first, some of the statements and definitions contained in the text of this volume may 
be similar to those in the former reports. Under the circumstances it is not necessary to 
set them off from the other text. 

In Part I of this volume are given the results of the investigations, and in Part II the 
abstracts or summaries of observations in the field and the descriptions of the stations. 

Anyone wishing to make a detailed study of the subject covered by this report should con¬ 
sult the four reports whose titles are given in the footnote on page 5. They may be obtained 
through the Division of Publications of the Department of Commerce, Washington, D. C. 



Part I.—INVESTIGATION OF GRAVITY AND ISOSTASY. 

Chapter I.—DEFINITION OF TERMS AND EXPLANATION OF METHODS OF COMPUTATION 

ISOSTASY DEFINED. 

If the earth were composed of homogeneous material, its figure of equilibrium, under the 
influence of gravitation a and its own rotation, would be an ellipsoid of revolution. 

The earth is composed of heterogeneous material which varies considerably in density. 
If this heterogeneous material were so arranged that its density at any point depended simply 
upon the depth of that point below the surface, or, more accurately, if all the material lying 
at each equipotential surface (rotation considered) were of one density, a state of equilibrium 
would exist, and there would be no tendency toward a rearrangement of masses. The figure of 
the earth in this case would be a very close approximation to an ellipsoid of revolution. 

If the heterogeneous material composing the earth were not arranged in this manner at the 
outset, the stresses produced by gravity would tend to bring about such an arrangement; but 
as the material is not a perfect fluid, since it possesses considerable viscosity, at least near the 
surface, the rearrangement will be imperfect. In the partial rearrangement some stresses will 
still remain, different portions of the same horizontal stratum may have somewhat different 
densities, and the actual surface of the earth will be a slight departure from the ellipsoid of 
revolution in the sense that above each region of deficient density there will be a bulge or bump 
on the ellipsoid, and above each region of excessive density there will be a hollow, relatively 
speaking. The bumps on this supposed earth will be the mountains, the plateaus, the conti¬ 
nents, and the hollows will be the oceans. The excess of material represented by that portion 
of the continent which is above sea level will be compensated for by a deficiency of density in the 
underlying material. The continents will be floated, so to speak, because they are composed 
of relatively light material; and, similarly, the floor of the ocean will, on this supposed earth, 
be depressed because it is composed of unusually dense material. This particular condition of 
approximate equilibrium has been given the name “isostasy.” 

The adjustment of the material toward this condition, which is produced in nature by the 
stresses due to gravity, may be called the “isostatic adjustment.” 

The compensation of the excess of matter at the surface (continents) by the deficiency of 
density below, and of surface deficiency of matter (oceans) by excess of density below, may be 
called the “isostatic compensation.” 

Let the depth below sea level within which the isostatic compensation is complete be 
called the “depth of compensation.” At and below this depth the condition as to stress of 
any element of mass is isostatic; that is, any element of mass is subject to equal pressures 
from all directions as if it were a portion of a perfect fluid. Above this depth, on the other 
hand, each element of mass is subject in general to different pressures in different directions— 
to stresses which tend to distort it and to move it. 

Consider the relations of the masses, densities, and volumes, above the depth of com¬ 
pensation, fixed by the preceding definition. The mass in any prismatic column which has 
for its base a unit area of the horizontal surface which lies at the depth of compensation, for 

a In this publication “gravity ” is the term used for the phenomenon of weight or of the acceleration of a body falling to the earth, and, at any 
place, it is the resultant of the earth’s attractive force, “gravitation,” and the centrifugal force due to the earth’s rotation. This distinction 
between the terms “gravity” and “gravitation ” is not always clearly drawn. 

In general it will be found that throughout this publication the attraction (expressed in dynes) is dealt with directly by preference rather 
than its numerical equivalent, the acceleration (expressed in centimeters and seconds). 


7 



8 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


its edges vertical lines (lines of gravity) and for its upper limit the actual irregular surface 
of the earth (or the sea surface, if the area in question is beneath the ocean), is the same as 
the mass in any other similar prismatic column having any other unit area of the same surface 
for its base. 

ASSUMPTIONS MADE IN REGARD TO THE TOPOGRAPHY AND ISOSTATIC COMPENSATION. 

For the purpose of making the computations by the Hayford method the earth's crust is 
assumed to be in a state of perfect isostasy, with each topographic feature compensated for by 
a deficiency (or excess) of mass directly under it, and it is assumed that this compensating 
deficiency (or excess) of mass is uniformly distributed to a depth of 113.7 km. This depth is 
that resulting from the first investigation by Hayford given in the Figure of the Earth and 
Isostasy from Measurements in the United States. 

The mean density of the solid portion of the earth’s surface is assumed to be 2.67 and the 
density of the ocean water 1.027. There is no assumption regarding the normal densities in the 
earth's crust below sea level. This fact should be clearly borne in mind, for a failure to realize 
this has been confusing to some who have considered the question of isostasy. It is simply 
assumed that the arrangement of the densities in the crust under a coastal plane at zero eleva¬ 
tion is normal and that the densities under the continents, islands, and the oceans depart from 
the normal condition by the amount necessary to distribute the isostatic compensation uni¬ 
formly with respect to depth of compensation. For our purpose a knowledge of the actual 
density at any given depth is unnecessary. 

The writer does not believe any one of the assumptions stated above is exactly true. The 
average density (from Harkness’s The Solar Parallax and Its Related Constants, p. 92) is 
certainly in error for the surface materials at many stations. The depth of compensation has a 
large probable error and may be largely in error for any given place. As it is the average or 
mean depth it may be subject to an actual error of considerable size. It is probable that the 
compensation for a topographic feature is not always distributed with exact uniformity with 
respect to depth. And it is also probable that the compensation is not located directly under a 
topographic feature. It may have a greater horizontal extent than the feature. The anomalies 
or differences between the observed gravity and the computed gravity give an idea of the extent 
to which the assumptions are not true. These differences are due partly to errors in the observa¬ 
tions and computations, but mostly to departures from the conditions postulated. But it may 
be stated that the results show that the continents as a whole are almost perfectly compensated 
and that this is the condition with respect to large portions of a continent. One of the im¬ 
portant problems of the geodesist is to determine the limits of the areas which may not be at 
least partly compensated. 

CHANGE OF SIGN DUE TO DISTANCE. 

The reader should consult pages 65 to 70 of Special Publication No. 10, which deals with the 
change of sign of the effect of topography and compensation due to distance. 

In nearly all cases the combined effect of the topography and compensation changes sign 
from plus to minus before zone L is reached. This zone has an inner limit which is only 19 
km. from the station. This is an important matter which should be considered by anyone 
studying the question of isostasy and its effect upon the intensity of gravity. One might 
assume without due consideration that in a mountainous region a station should have large 
positive corrections for each of the near zones, say within zone N, outer limit 99 km., while they 
may have large negative values. Pikes Peak, for example, has corrections of —0.0290 and 
— 0.0334 dynes, respectively, for zones M and N. 

The explanation of the change in sign is given in detail in Special Publication No. 10. 
Briefly, it is that near the station the topography has the predominating effect, as it is much 
closer than the center of mass of the compensation. As the distance from the station increases 
the ratio between the sine of the depression angle to the center of the compensation and the 
sine of the angle of elevation or depression to the center of the topography becomes greater. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


9 


At the same time the ratio of the distances to the compensation and to the topography becomes 
less. Therefore at a certain distance the vertical component of the effect of the compensation 
becomes greater than that of the topography. 

It is evident that at great distances from the station the effect of the compensation will be 
greater than the topography. It should be noted that the effect of topography in the oceans is 
negative and its compensation positive. This fact causes the combined effect for the more 
distant zones, which cover water areas mostly, to be positive. These facts may be observed by 
referring to the table given on pages 20-48. 

REDUCTION TABLES FOR EFFECT OF TOPOGRAPHY AND ISOSTATIC COMPENSATION. 

The tables for making the reduction for topography and compensation were computed 
upon the theory that the earth’s crust is in a state of perfect isostasy with a surface density of 
2.67 and a density of water in the oceans of 1.027, that the compensation is complete directly 
under the topography, and that the depth of compensation is 113.7 km. These tables with 
detailed statements as to the methods employed in computing them, and directions for using 
them are printed in Special Publication No. 10, entitled, “The effect of topography and iso¬ 
static compensation upon the intensity of gravity,” United States Coast and Geodetic Survey, 
1912. It is not desirable to repeat the tables with descriptions showing how to use them. The 
tables are made for 33 zones, which cover the entire surface of the earth, it having been found 
that the resultant attraction of the topography and compensation even at the antipodes must 
be taken into account. 

It has been found possible to save much effort in making the computations by interpolating 
the values for the effect of the topography and compensation for the outer zones for a station 
from the values for those zones computed for surrounding stations. The saving will be greater 
when the new station is very close to the stations used for the interpolation. The subject of 
interpolation is discussed fully on pages 58 to 65 of Special Publication No. 10. 


CORRECTIONS AND ADDITIONS TO TABLES. 


Since its publication some errors were discovered in the reduction table for zone C. This 
table is repeated below with the corrected numbers in boldface type. These errors had no 
appreciable effect on the results of the investigations reported in Special Publications Nos. 
10 and 12. 

On pages 11 to 18 there are given additional tables which should be used when computing 
the effect of topography and compensation for the close topography at mountain stations. 
(See p. 94.) 

For computing the effect of using the tables for a subdivided zone instead of the table 
for the entire zone, the elevation of the entire zone must be made consistent with the eleva¬ 
tion of its parts. If \ and h 2 are, respectively, the elevations of the inner and outer subzones 
and h the average elevation of the entire zone, then, 


for zone C, 
for zone D, 
for zone E, 
for zone F, 


7i = 7i 2 +0.255 (^ — h 2 ), 
7i. = 7i 2 -t-0.310 (Ji x — 7i 2 ), 
Ji = h 2 ~\~0.317 (Tij — 7i 2 ), 
h — Ti 2 ~\- 0.328 (7&1 — 7?< 2 ). 


In conformity with the reduction tables in Special Publication No. 10 all tabular values 
in the following tables are expressed in units of the fourth decimal place in dynes. 


10 


Si 

i 

© 

N 

s* 

© 

r-C 

e 

ss 

o 

•<s> 

■8 

'Sj 

+ 

<» 

>o 

>» 


e 


5 

a 


& 

a 

o 

o 

fc- 

s 

o 

ft 


8 


3 
—■ 
3 


3 

O 


'd 

c3 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 




600 

feet 



to 

CO 

1 

o cm a to 

CO CO CM CM CM 

1 1 1 1 1 

1 1 1 1 1 

© X X X X 

!—4 1—4 t—4 i-H 1-4 

1 1 II 1 

xxxx 

7777 



500 

feet 



© CM 

CO CO 

1 1 

05 CO CM i-4 © 

CM CM CM CM ©9 

1 1 1 1 1 

©oo co co 

1—( i—4 i—4 f—4 i—4 

1 1 1 1 1 

© © © © © 
77777 

to © © © 

1—4 1—4 1—4 —H 

1 1 II 



450 

feet 



-28 

-28 

88S22 

1 1 II 1 

© to to TP 

1—4 1—4 r—4 1—4 1—4 

1 1 1 1 1 

Tp TP TP CO CO 

77777 

XXXX 

1—4 1—4 1-H 1—4 

1 1 1 1 



400 

feet 



ssss 

1 1 1 

CM O 00 CO tO 

CM CM —4 -4 1-H 

1 1 1 1 1 

tp tp co co co 

77777 

CM CM CM CM CM 

1—4 1—4 1 -H r—4 1—4 

1 1 1 1 1 

CM CM CM CM 

1—4 1—4 1-H 1—4 

1 1 1 1 


+-> 

350 

feet 



<Me-4 
CM CM CM 

1 1 1 

05 r— to co 

77777 

CM CM H i—4 i-H 

77777 

© © © © © 
77777 

©© ©© 
7777 


s 

a 

-*-> 

M 

03 

ft 

300 

feet 



© 00 00 00 

7777 

CO TJ4 ©1 1-4 1-4 

77777 

© © © © © 
i—4 i—4 

1 1 1 1 1 

©xxxx 

1 1 1 1 1 

xxxx 

1 1 1 1 


a 

o 

o 

* 

o 

o 

« 

250 

feet 



Tp © »0 tP 

7777 

©9 1-4 © © 00 

777 i i 

oo r- p- r- u- 

1 1 1 1 1 

p- © © © © 

1 1 1 1 1 

co CD to © 

1 1 1 1 

1 


200 

feet 



05 H CM © 

1—4 1—4 H i—4 

1 1 1 1 1 

05 00 t" CO CO 

1 1 1 1 1 

© to to to to 

1 1 1 1 1 

© © TP Tp T#4 

1 1 1 1 1 

HJ4 TP TJ4 TP 

1 1 1 1 



150 

feet 


© 

1 

p-x xx p- 
II 1 1 1 

© tO to Tp TP 

1 II 1 1 

■»T tp tP X X 

1 II 1 1 

CO CO co CO CO 

Mill 

xxxx 

1 1 1 1 

1 

g 


100 

feet 


cm cc 

1 i 

t*4 © tp tp tP 

1 1 1 1 1 

TP X CM CM CM 

1 1 1 1 1 

CM CM CM ©9 CM 

1 1 II 1 

1—4 1—4 —H f—4 1—4 

II 1 1 1 

7777 

c3 

45 

K 

1 

O 


50 

feet 


7777 

CM CM CM CM CM 

1 1 1 1 1 

CM 1-4 r-H 1—4 1—4 

1 1 1 1 1 

1-4 W©©© 

1 1 

©©©©© 

©©©© 

.2 

S3 

> 

0> 

% 


600 

feet 


+++++ 

© 1-1 T* © © 

1 1 1 1 

© 1-4 CO CO TT 

17777 

TfiOONP* 

77777 

1- P- P- X X 

77777 

xxxx 

7777 

o 

a 

o 

o 

C/ 

k 

M 

O 

O 


11 


H H (N 

+ + + + + 

r-» © £9 tP © 

+ III 

00 © o -4 CM 

i 1777 

CO CO CO Tf TJ1 

77777 

1+ •*+ Tf © © 

77777 

© © to © 

7777 


450 

feet 


i-i r~ 1-4 £9 £9 

+ + + + + 

©1 © TH -0 --*4 

+ III 

co x 05 © © 

i i 177 

i-4 i-4 CM ©9 CM 

77777 

CO CO CO CO CO 

77777 

xxxx 

7777 



400 

feet 


+ + + + + 

©9*-4©©l4*4 

+ -f 1 1 

uSt-OOSSCt 

1 1 1 1 1 

©© ©© © 
77777 

77777 

1-4 iH 1—4 —H 

7777 


4J 

a 

© 

a 

350 

feet 


w 

+++++ 

©1 p-4 © tH C5 

+ 4- 1 1 

tj4L50t^CC 

1 1 1 1 1 

x x oc © © 

II 1 1 1 

© © © © © 

17777 

© © © © 
7777 


u 

03 

ft 

g 

O 

g® 

© 


h ©j n 05 
+ + + + + 

£9 ©9 —4 © ©9 
+ + + | 

C 5 tP © © © 

1 1 1 1 1 

© p-p- r^oo 

1 1 1 1 1 

X X X X X 

1 1 1 1 1 

xxxx 

1 1 1 1 


> 

o 

£ 

<< 

250 

feet 


t-< ©1 £9 ©3 OS 
+ + + + + 

C5 ©9 t- © t- 

+ + + 1 

01 X TP Tp t+ 

1 1 1 1 1 

to to to © © 

1 1 1 1 1 

© © © © © 

1 1 II 1 

© © © © 

1 1 1 1 



200 

feet 


©1 ©1 ©1 05 
+ + + ++ 

C5 ©1 ©9 i— © 

+ + + + 

tH ©1 ©9 CO CO 

1 11 1 1 

CO CO tP tP Tp 

1 1 1 1 1 

Hfl TJ4 Hjl ^ 

1 1 1 II 

HP TP TP HP 

1 1 1 1 



150 

1 feet 

o 

pH ~ ©1 ©J ©5 
+ + + + + 

C5C5©1 ©9 ** 
+ + + + + 

©*—*- — ©1 

1 1 1 1 

09 CM CM CM CM 

1 1 1 1 1 

CM CM X CO X 

1 1 1 II 

CO x X X 

II 1 1 



100 

feet 

© 

TH —1 ©J ©1 ©1 

4- + + + + 

©9 ©9 ©9 ©9 H 

-f 4* 4-H - + 

F-4 ©© ©-4 

+ 1 

HH H P« H 

1 1 1 1 1 

^-4 ^4 ^4 T—4 

1 1 1 1 1 

HHihh 

1 II 1 



50 
j feet 

o 

+ + + + 

©9 ©9 »-4 1-4 — 

4-4-4-4-4- 

0 

0 

0 

0 

T + 

sseee 

©©©©* 

oocc 

i 

t— 

Topog- 

raphy 

and 

com¬ 

pensa¬ 

tion 

05 **p 

1 1 

COhhcO 

+ + + 

hP X CM © X 

+ + + + 4“ 

+22 
+26 
+ 28 
+31 
+32 

TP © P- X C5 
X CO CO CO CO 

4-4-4-4-4- 

C © 1-H 1-4 CM 

TP rjl Tf TJ4 ^?4 

+ -M- + + 

X CM CM CM 

TP TP TP -J* 

+ 4- + + 

.2 

i "7; 

<» 

: Com¬ 

pen¬ 

sation 

©o 

©ooe © 

©©©©© 

©©©©© 

©©©©© 

© i-H i—4 —4 1—4 

1 1 1 1 

tH CM CM CM 

II 1 1 

- 

Topog¬ 

raphy 

05 

i i 

OOHHM 

+ + + 

tP 00 CM to 00 

4-4-4-4-4- 

CM CO 00 i—4 CM 
©9 CM CM CO CO 

4-4-4-4-4- 

TP © 00 © 

X CO X X CO 

4-4-4-4-4- 

© i-H CM CM X 

TP T*> Tf TP TJ4 

4- + + + + 

TP Tp Tp TP 

Tp TP TP -p 

+ + + + 

Mean 
elevation 
of com¬ 
partment 

Fathoms 

-80 

-40 

WOiCCO 

cm © p- © © 

"JH 1—4 1-H 

9 

e 

ggggg 

CM CO Tp IO © 

800 

1 000 

1 200 

1 400 

1 600 

1 800 

2 000 

2 500 

3 000 

3 500 

ggggg 
© © © © © 

© ©X © 

hH 

12 000 
14 000 
16 000 
18 000 


40. 


a This table should be used instead of the table for zone C as given on p. 31 of Special Publication No. 10. 
































































REDUCTION TABLES FOR DIVIDED ZONES. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


11 


e 

© 

N 


a 

5 

B 


a 

P, 


P 

o 

pH 


1 


a 

o 


S 

© 

a 


a 

•3 





600 

feet 


00 

rH 

1 

N iO fO N H 

77777 

t"H O O © O 

77777 

05 C 5 05 05 05 

1 1 1 1 1 

05 05 05 ©i 

1 1 1 1 




500 

feet 


CO CO 

>H tH 

1 1 

TfNOHO 

t-H 1—4 i —4 i —4 r-H 

1 1 1 1 1 

05 05 05 CO 00 

1 1 1 1 1 

xxxxx 

1 1 1 1 1 

xxxx 

1 1 1 1 




450 

feet 


to -tfi 
t-H i —4 

1 1 

CM O O 05 © 

777 i i 

00 00 00 CO 00 

1 1 1 1 1 

r» r>- w t>. 

1 1 1 1 1 

t— t—I— 

1 1 1 1 




400 

feet 


CO CO 

rH rH i —4 

1 1 1 

1-H 05 00 00 00 

7 i i i i 

1 1 I 1 1 

l» D- !>• 

1 1 1 II 

t-NNN 

1 1 1 1 



4-5 

350 

feet 


CM CMrH 
H H H 

1 1 1 

OCONNN 

7 ii i i 

cO cO cO co co 

1 1 1 1 1 

co CO CO co co 

1 1 1 1 1 

CO COCOc© 

1 1 1 1 



fl 

© 

a 

*h 

C 3 

pH 

300 

feet 


O-H oo 

rH tH i —4 

1 1 1 1 

oo r- o co co 

1 I 1 1 1 

XI O iC lO |Q 

1 1 1 1 1 

to to to 10 to 

1 1 1 1 1 

t© tQ to to 

lilt 



a 

o 

© 

£ 

o 

250 

feet 


00 00 00 t— 

1 1 I 1 

CO tO t© hJt rf 

1 1 1 1 1 

r }4 -rfi r * 4 -34 t *4 

1 1 1 1 1 

Tj 4 H* 4 Tt 4 T* 4 Tt 4 

1 1 1 1 1 

Tt 4 TJ 4 r}4 -H 4 

1 1 1 1 



« 

200 

feet 


io r- r- co »o 

1 1 II 1 

■r }4 -f 4 T }4 CO CO 

I 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

X X X CO CO 

1 1 1 II 

xxxx 

1 1 1 1 




150 

feet 

CO 

1 

Mill 

CO CO CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

Mill 

CM CM CM CM CM 

1 11 II 

CM CM CM CM 

1 1 1 1 

1 



100 

feet 

CM M 

1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM t— 4 i —4 rH i —4 

1 1 1 1 1 

1—4 T-H i-H r-H 1—4 

1 1 1 1 1 

t-H rH t-H t —4 1—4 

1 1 1 1 1 

7777 

1 

"3 

in 

*—> 



50 

feet 

O 0 »-H f-H t -4 

1 1 s 

rH rH tH tH 

1 1 I 1 1 

i—ti—tO O 

1 1 

ooooo 

ooooo 

0000 

a 

o 

-T~* 

c 3 

> 



600 

feet 

ooooo 

i-H CM O «0 

1 1 1 1 1 

t- rococo oo 

1 1 1 1 1 

X X 05 05 05 

1 1 1 1 1 

05 05 05 05 05 

1 1 1 1 1 

05 O 05 05 

1 1 1 1 

*© 

u 

a 

c 

o 



500 

feet 

o o o o o 

T-H CM CO ^ >0 

1 II 1 1 

OONM't 

1 1 1 1 1 

r» i>-xxx 

1 1 1 1 1 

xxxxx 

1 1 1 1 1 

00 CO co 00 

1 1 1 1 

© 

o 

O 



450 

feet 

ooooo 

©CMX ** 

1 II 1 

to CO c© CO CO 

1 1 1 1 1 

cot>-t^r-i— 

1 1 1 1 1 

f- t'- t>- t-V. I-H. 

1 1 1 1 1 

r- r- 

1 1 II 




400 

feet 

o ^H tH *H O 
+++ 

Ot-H CM CO Tt 4 

1 1 1 1 

to t© c© c© c© 

Mill 

0 CO 0 CO co 

1 1 1 1 1 

cO CO cO CO cO 

1 1 1 1 1 

• {© c© {© *© 

1 II 1 



4-3 

© 

a 

350 

feet 

OHHHH 

++++ 

© rH CM CM X 

1 1 1 1 

Tf 4 Tt 4 t© l© t© 

i i i i i 

t© l© t© i© t© 

1 1 1 1 1 

tO to tO to to 

1 1 1 1 1 

to »0 to to 

1 1 1 1 



s 

P< 

a 

o 

© 

© 

1> 

o 

-O 

◄ 

300 

feet 

O ^ 

++++ 

O Ot-H CM CO 

1 1 1 

CO CO Tf Tf T* 

1 1 1 II 

T #4 Tr* to to 

1 1 1 1 1 

1 © 1 - 0 to to 

1 1 1 1 1 

to to to to 

1 1 II 



250 

feet 

rH rH rH •—I 
++++ 

H O t-H *-H CM 

+ ill 

CM CO CO CO CO 

1 1 1 1 1 

CO CO Tf Tf 4 

1 1 1 I 1 

1 1 1 1 1 

Hf 4 H-f4 r* 4 HJ 4 

1 1 1 1 




200 

feet 

QHHHH 
+ + + + 

t-H O © tH i—4 
+ 1 1 

CM CM CM CM CM 

1 1 1 II 

CM CM CM CO CO 

1 1 1 1 1 

xxxxx 

1 1 1 1 1 

xxxx 

1 1 1 1 




150 

feet 

C© rH rH rH ?-H 
+ + + + 

HHOOO 
+ + 

i-H i —4 i —4 1—4 i —4 

1 1 1 1 1 

1-H CM CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CM CM CM 

1 1 1 1 




100 

feet 

o rH tH i-H t-H 
+ + + + 

HHHHO 
+ + + + 

O O OtH 1-H 

1 1 

i-H *—4 t-H 1—4 1—4 

1 1 1 1 1 

rH rH rH i-H rH 

1 1 1 1 1 

T-H i-H i-H 1—4 

1 1 1 1 




50 

feet 

O OO ^4 
+ + 

^tHOOO 
+ + 

OOOOO 

ooooo 

ooooo 

0000 

i 

fa 

£ 


Topog¬ 

raphy 

ond 

auu 

com¬ 

pensa¬ 

tion 

OOOHN 

+ + 

CO »o CO 00 05 

+++++ 

T-H CM CO CO Tf 

++++7 

Tf« Tt* to O CO 

777-77 

CO CO CO CO c© 

77777 

co CO co co 

rH t— 4 t-H r-H 
++++ 

| 

© 


Com- 

lAiU’ 

sa- 

tion 

OOOOO 

ooooo 

ooooo 

ooooo 

ooooo 

rH 1—4 rH rH 

1 1 1 1 

fc! 

o 

O 


t 

e 

E- 

raphy. 

HNiOOON 

oodoH 

+++++ 

N 00 U 5 ON 

CMHjHcdooo 

+ + + + + 

05 OX TJ4 05 
O* CM CM CO cd 

T—4 i—l i-H 1-H 1—4 
+++++ 

co to i-H »o x 

Tj 5 rJH to id id 

T—4 1-H 1-H 1—4 —4 

+ + + + + 

O CM CO X 

CO cO cO CO cO 

77777 

0000 

t'C 

+ + + + 

Mean 
elevation 
of corn- 
part- 

•^4-3 

© 

U 

25 

50 

75 

100 

150 

200 

300 

400 

500 

600 

800 

1 000 

1 200 

1 400 

1 600 

1 800 

2 000 

2 500 

3 000 

3 500 

4 000 

5 000 

6 000 
8 000 

10 000 

12 000 
14 000 
16 000 
18 000 















































[Inner radius, 130 meters; outer radius, 230 meters. Four compartments.] 


12 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 





600 

feet 


7 

00 |H CD ^4 CO 

HHHHH 

1 1 1 I 1 

04 -4 O O 05 

7777 i 

05 05 05 C5 C5 

1 1 1 1 1 

05 05 C5 05 

1 1 II 




500 

feet 


Tt< ‘O 

—4 I-H 

1 1 

to rr 04 —40 

77777 

O 05 GO 00 00 

7 i ii i 

r- 

II II 1 

1 1 1 1 




S« 


CO Tf« 

rH i—4 

1 1 

CO 04 -4 o 05 

7777 i 

co oo in r>. 

i i i i i 

CD CD CD CD CD 

1 1 I 1 1 

CD CD CD CD 

II II 




400 

feet 


O —« ©4 

777 

-4005 GO 00 

77 i i i 

t"- CD CD CD 

II 11 1 

• 

CD tO to tD iO 

1 1 1 1 1 

to to to to 

1 1 1 1 



4-2 

£ 

© 

350 

feet 


ooo 

—*4 r—4 

1 1 1 

O 05 00 !>• CD 

7 i i i i 

CD CD tD ID O 

1 II II 

tO Tfl Tj< T* 

1 II II 

-T 1 TJ< TT< TJ< 

1 1 1 1 



a 

4-9 

t— 

a 

o 

300 

feet 


CD 00 00 05 

1 II 1 

CO t"- CD CD to 

1 II 1 1 

II II 1 

T CO CO CO co 

II II 1 

CO CO CO CO 

1 II 1 



© 

£ 

o 

250 

feet 


(DCNN 

1 1 1 1 

CD »0 ‘O rf ■n* 

1 1 1 1 1 

*1* CO CO CO CO 

II II 1 

CO CO CO 04 04 

II II 1 

©4 ©4 ©4 ©4 

1 II 1 

1 



200 

feet 


CO 'rf* »D ‘O »D 

1 1 1 1 1 

>0 T H COCO 

1 1 1 1 1 

CO 04 04 04 04 

II II 1 

04 04 04 C4 04 

II II 1 

©4 ©4 ©4 ©4 
1111 

£ 

.2 

-t-2 

03 

4-» 

CO 



150 

feet 

©4 

1 

04 CO T ■n’ CO 

1 1 1 1 1 

CO CO 04 04 04 

Mill 

04 04 —4 -4 rH 

II 1 1 1 

77777 

7777 

O 

£ 

•2 

t 



100 

feet 

77 

-4 04 ©4 ©4 04 

1 1 1 1 1 

04 04 —4 -4 -4 

1 1 1 1 1 

rHr-H W C 

II II 

ooooo 

o o o o 

JD 

% 

O 

£ 



50 

feet 

O O O O -H 

1 

77777 

--HHHO 

Mil 

OOOOO 

ooooo 

o o o o 

8 

B 

o 



600 

feet 

hhhhN 
+++ + + 

rH -4 O O -4 
+ + 1 

CO TT4 to CD CD 

II II 1 

cd u- r>- oo oo 

II II 1 

00 00 00 00 00 
II II 1 

CO CO 00 00 
1111 




500 

feet 

OhhhCI 

+ + + + 

04 04 h O O 
+ + + 

04 CO rf TT to 

II II 1 

O »0 CD CD CD 

1 1 1 l l 

CDONNN 

II II 1 

t'- t'- L- 

1 1 1 1 




450 

feet 

+ + + + 

04 04 ^ —4 O 

+ + + + 

—4 04 CO •*+ 

II II 1 

-f »© to to »rj 

1 1 1 1 1 

CD CD CD CD CD 

II II 1 

O CD O CD 

II II 




400 

feet 

OHHHN 

+ + + + 

04 04 04 —i O 
+ + + + 

-4 04 04 CO CO 

II II 1 

CO —*« Hf 1© 

Mill. 

to to to to »o 

1 1 1 1 1 

to to »o to 

1 II 1 



£ 

© 

a 

350 

feet 

OHH^N 

+ + + + 

04 04 04 *h O 
+ + + + 

—' T-H 04 04 04 

II II 1 

CO CO CO Tt* 43* 

II II 1 

Tt< -f Tfl T+ •*+. 

II II 1 

rf rf -J. TI< 

1 1 1 1 



cJ 

Pi 

a 

o 

© 

300 

feet 

OhhhN 
+ + + + 

04 04 04 -4 r-4 
+ ++ + + 

O —4 r-4 04 04 

II II 

04 04 CO CO CO 

II II 1 

CO CO CO CO co 

II II 1 

CO ?0 CO CO 

II II 



© 

> 

o 

<1 

250 

feet 

O rH —4 ©4 

+ + + + 

04 04 04 —« —4 
+ + + + + 

OOhhh 

1 1 1 

rH Ol 04 04 04 

11 1 II 

04 ©4 04 ©4 04 

II II 1 

©4 ©4 ©4 ©4 

II II 



200 

feet 

OHHHM 

+ + + + 

04 04 -4 rH rH 
+ + + + + 

-<000-4 
+ 1 

—4 —4 —4 rH 04 

II II 1 

©4 ©4 ©4 ©4 ©4 

II II 1 

©1 ©4 ©4 ©4 

II II 




150 

feet 

0 

+ + + + 

04 04 -4 -4 rH 
+ + + + + 

-40 000 

+ 

°7777 

77777 

7777 




100 

feet 

o O —4 1-4 1-4 

+ + + 

+ + + + + 

-4-4000 
+ + 

ooooo 

ooooo 

oooo 




50 

feet 

0 0 0 0-4 
+ 

HHHHH 

ooooo 

ooooo 

ooooo 

o o oo 

1 

Topog¬ 

raphy 

and 

compen¬ 

sation 

OOOOrH 

+ 

04 co 4© oo 

+ + + + + 

04 r* CD 00 

77777 

05 O 04 CO CO 
-4 04 04 04 04 

+ + + + + 

t* to to CD CD 
©4 ©4 ©4 ©1 ©4 

+ + + + + 

CO CD CD CD 
©4 ©4 ©4 ©4 

+ + + + 

O 

£ 

o 

8 

t 

Compen¬ 

sation 

ooooo 

ooooo 

ooooo 

OOOOO 

OOOOO 

rH r—4 rH rH 

1 1 II 


Topog¬ 

raphy 

0 

+ 0.1 
+ 0.2 
+ 0.4 
+ 0.9 

CD 04 O 00 tO 

—4 CO tO CD 00 

+ ++++ 

IOOCNC4CO 

—4 CO to I'- 00 

77777 

+ 19.3 
+ 20.1 
+ 21.6 
+22.6 
+ 23.3 

+23. 9 
+ 24.7 
+ 25.2 
+ 25.9 
+26.3 

+ 26.6 
+ 26.8 
+ 27.0 
+27.1 

Mean ele- 

vation of 
compart¬ 
ment, 
in feet 

WOICOO 
©4 tO O ‘O 
^ -4 


800 

1 000 

1 200 

1 400 

1 600 

1 800 

2 000 

2 500 

3 000 

3 500 

TflOCDXO 

rH 

12 000 
14 000 
16 000 
18 000 
































































Zone D t . 

[Inner radius, 230 meters; outer radius, 380 meters. Six compartments.IJ 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 13 





1100 

feet 



©©©©O 
fH i—4 CM CM CM 

Mill 

© © 00 00 tf 

77777 

© © © tp CO 

77777 

CO CO CM CM CM 

77777 

HHOOO 

H rt 1—4 1—4 i-H 

1 11 1 1 

©©©©© 
FH 1—4 FH 1—4 

1 1 1 1 1 

© © © © © 

1 1 1 1 1 

© © 

1 1 




O +J 

O © 



00 00 00 00 

F—4 1-H i—4 i—t i—4 

t'- b- © © © 

fH 1—4 1—4 1—4 1—4 

© Tp CO CM CM 

hhhhO 

© © © © © 
1—4 1—4 

© © © © © 

©oooooooo 

00 00 




O © 
f-l 


1 

1 1 II 1 

1 1 1 1 1 

1 1 1 i 1 

1 1 i l l 

1 1 1 1 1 

1 1 1 1 1 

1 1 1 1 1 

1 1 




900 

feet 


© co 

fH fH 

1 1 

co © © © © 

fH i-H fH i—4 1-H 

1 1 1 1 1 

© © Tp TP TP 
rH fH i-H fH rH 

1 1 1 1 1 

CO CM H HO 

F-H 1—4 1-4 F-H 1—4 

1 1 1 1 1 

© © © © © 
777 i i 

© 00 00 00 00 

1 1 1 1 1 

oo oo oo oo oo 

1 1 1 1 1 

oooooct>»t>» 

1 1 1 1 1 

tf tr. 

1 1 




800 

feet 


CO CO tp 

777 

Tp —p Tp Tp Tp 

77777 

CO CO CO CM fH 
fH 1—4 1—4 1—4 i-4 

1 I 1 1 1 

fH O O © © 

777 i i 

© 00 00 00 00 

1 1 1 1 1 

NNNtrN 

1 1 1 1 1 

NNNNN 

1 1 1 1 1 

r-NtrD© 

1 1 1 1 1 

© © 

1 1 



+3 

P 

© 

a 

■4-3 

700 

feet 


O f-4 03 CM 

7777 

CM CM CM CM H 

77777 

fH ^4©©© 

77777 

© © oo oor>» 

1 1 1 1 1 

I s - r>-1"- r— © 

i i i i i 

© © © © © 

1 1 1 1 1 

© © © © © 

1 1 1 1 1 

© © © © © 

1 1 1 1 1 

© © 

1 1 



09 

Oh 

fl 

o -*-» 


00©©©© 
1—4 1—4 F—4 

© © © © © 
i—4 <—4 1—4 i-H 

© © © 00 00 

00 NNDCO 

© © © © © 

©©©©Tp 

TP Tp Tp Ip Tp 

TP Tf Tp TP P 

TP Tp 



O 

© 

> 

s © 

^ **H 


1 1 1 1 1 

1 1 1 1 1 

1 1 1 1 1 

1 1 1 1 1 

Mil! 

1 1 1 1 1 

1 1 1 1 1 

1 1 1 I 1 

1 1 



o 

« 

500 

feet 

CO 

1 

00 00 00 00 

1 1 1 1 1 

00 00 00 00 If 

1 1 1 II 

tr» © © © 

I 1 1 1 1 

CD © © © © 

1 1 1 1 1 

TP Tp Ip Tp TP 

1 1 1 1 1 

TP TP TP CO CO 

1 1 1 II 

CO CO CO CO CO 

1 1 1 1 1 

co co co co co 

1 1 1 1 1 

CO co 

1 1 




400 

feet 

tp © 

1 1 

CO co co co co 

1 1 1 1 1 

© © © © © 

1 1 1 1 1 

© © © © Tp 

1 1 1 1 1 

Tp Tp TP CO CO 

1 1 1 1 1 

CO CO CO CO co 

1 1 1 1 1 

CO CO CO CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 II 

CM CM CM CM CM 

1 1 1 1 1 

CM CM 

1 1 

1 

g 



300 

feet 

CM CO tp 

1 1 1 

■'l 1 ^ 

1 I 1 1 1 

TP TP TP Tp Tp 

1 1 1 1 1 

co co co coco 

1 1 1 1 1 

CO CO CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

FH i—4 i—4 1—4 1—4 

1 1 1 1 1 

77777 

f—4 1—4 f-4 f—4 1—4 

1 1 1 I 1 

F—4 i—4 

1 1 

03 

4-3 

w 

C 

g 



200 

feet 

fh cm cm cm 

1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO CM CM CM CM 

1 1 II 1 

CM CM CM CM CM 

1 1 1 1 1 

iH i-H fH fH f—4 

1 1 1 1 1 

f—4 i—4 i—4 i—4 —4 

1 1 1 1 1 

77777 

77777 

77777 

F—4 fH 

1 1 

-+-> 

a 

> 

9 

*© 



100 

feet 

O »“H fH fH 1—4 

1 1 1 1 

i-H hhhh 

1 1 1 1 1 

F—4 i—4 1—4 i-H 1—4 

1 1 1 1 1 

77777 

HHOOO 

1 1 

©©©©© 

o© o ©o 

©© © © © 

© © © © © 

© © 

In 

O 

C 

o 



1100 

feet 

+ + + + + 

OOHHd 

1 1 1 

cm co co tp -p 

1 1 1 1 1 

Tp tP Tp © © 

1 1 1 1 I 

© © © f”- 1-- 
1 1 1 1 1 

t- 00 00 oo oo 

1 1 1 1 1 

00 00 00 00 © 
11 1 1 1 

© © © © © 
i i i i i 

© © © © © 
i i i i i 

© © 

1 1 

i 

o 

O 



1000 

feet 

HHfNHH 

+ + + + + 

HO O fH 
+ 1 1 

CM CM CM CO CO 

1 1 1 1 1 

Tp Tp TP Tp © 

1 1 1 1 1 

© © CD © © 

1 1 1 1 1 

1 1 1 1 1 

t'- 00 00 00 

1 1 1 1 1 

00 00 00 00 00 

1 1 1 1 1 

00 00 00 00 00 

1 11 1 1 

00 00 

1 1 




900 

feet 

_ 

HHNNH 

+ + ++ + 

i—4 i-H o O fH 

+ + 1 

F-4 CM CM CM CO 

1 1 1 1 1 

CO CO CO Tp Tp 

1 1 1 1 1 

Tp © © © © 

1 1 1 1 1 

© © © © © 
i i i i i 

©©ItMt 

1 1 1 1 1 

r>- t>- if i'-r- 
1 1 1 1 1 

II 1 1 1 

t'-l>- 
1 1 




800 

feet 

+ + + + + 

_H _ O © 

+++ 

fH »-4 1-4 CM CM 

1 1 1 1 1 

CM CM CO CO CO 

1 1 1 1 1 

Tp TP TP Ip © 

Mill 

© © © © © 
i i i i i 

© © © © © 

1 1 1 1 1 

© © © © © 
i i i i i 

© © © © © 

1 I 1 1 1 

© © 

1 1 



-H3 

g 

a 

-*-> 

700 

feet 

Hd(NC4(N 
+ + + + + 

NhhhO 

++++ 

O O F-4 F-4 1-4 

1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CO CO CO CO T+ 

1 1 1 1 1 

Tp Tp Tp Tp TP 

1 1 1 1 1 

Tp © © © © 

1 1 1 1 1 

© © © © © 
i i i i i 

© © © © © 

1 1 1 1 1 

© © 

1 1 



c3 

Oh 

a 

o 

© 

600 

feet 

+ + + + + 

CM CM ^4 fH i-H 
+++++ 

©©©©fH 

1 

i—4 i-H fH i-H CM 

1 1 1 1 I 

CM CM CM CO CO 

1 1 II 1 

co co co co co 

1 II 1 1 

CO Tp Tp TP Tp 

1 1 1 1 1 

TP Tp Tp Tp Tp 
11 1 1 1 

TP Tp Tp TP Tp 

1 1 1 1 1 

Tp Tp 

1 1 



© 

> 

o 

-o 

<1 

500 

feet 

+ + + + + 

CM CM CM F-I F-4 
+ + + + + 

HHOOO 

+ + 

ohhhh 

1 1 1 1 

f-h f-4 CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CO CO CO CO 

1 1 1 1 1 

CO CO CO CO CO 

II 1 1 1 

CO coco CO CO 

1 1 1 II 

coco 

1 l 




400 

feet 

fH fH CM CM CM 
+ + + + + 

CM CM CM CM >-4 
+ + + + + 

fH i—4 i—4 i—4 O 
+ + + + 

©© © ©© 

77777 

fH fH rH CM CM 

1 1 1 1 I 

CM CM CM CM CM 

1 1 1 1 I 

CM CM CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CM 

1 1 




300 

feet 

HHINNN 
+ + + + + 

CM CM CM CM CM 
+ + + + + 

fH i—4 i-H i—4 fH 

+ + + + + 

HO©©© 

+ 

©ooo© 

i—4 fH i—l i—4 i—4 

1 1 1 1 1 

i—4 fH f-H f-4 i—4 

1 1 1 1 1 

i—4 i—4 i—4 i—4 i—4 

1 1 1 1 1 

77777 

f- 4 i—4 

1 1 




200 

feet 

hhhhN 

+ + + + + 

CM N »H H H 

+ 4- + + + 

+ + + + + 

HHOOO 

++ 

© © © © © 

© © © © © 

©©©©© 

© © © fH H 

1 1 

t— 4 1—4 i—4 f—4 i—4 

1 1 1 1 1 

77 




100 

feet 

Ohhhh 

+ + + + 

f-4 i—4 i—4 f-H fH 

+ + + + + 

f-4 i-H i—4 f-H i-H 

+ + + + + 

©ooo© 

©o©o© 

©©©©© 

©©©O© 

©©© ©© 

©©©©© 

©© 

A 


Topog¬ 

raphy 

Ur-LLU. 

com¬ 

pensa¬ 

tion 

OHHNM 

+ + + + + 

tp © «D 00 

© © f-4 CM CM 

i-H i-H f-H i—4 

+ + + + + 

CO tp Tp © © 

+ + + + + 

© r>- oo oo © 

+77+7 

+ 19 
+ 20 
+ 20 
+ 21 
+ 21 

CM CM CO CO CO 
CM CM CM CM CM 

+ + + + + 

Tp TP Tp TP TP 

CM CM CM CM CM 
+ + + + + 

Tp Tp © © © 

CM CM CM CM CM 
+ + + + + 

+ 25 
+ 25 

*2 

a 

o 

I 


Com- 

pensa- 

tion 

ooo oo 

©OOO© 

© © © © © 

© © © © © 

©ooo© 

© © © © © 

© ©©©© 

1—4 fH f—4 i—4 fH 

1 1 1 1 1 

fH F-4 i-H 1-4 f-4 

1 II 1 1 

77 

i 

o 


Topog¬ 

raphy 

+ 0.1 
+ 0.6 
+ 1.2 
+ 2.1 
+ 3.1 

CM CO CO CO 
+ »o co I s - oo 

+++++ 

+ 9.3 
+ 10.2 
+ 11.0 
+ 11.8 
+ 12.5 

CM © © © © 
CO co + © © 

1—4 1—4 1—4 1—4 i-H 

rp CO © © CM 

© 00 00 © 

1—4 1—4 1—4 F-4 f-4 

+++++ 

+ 19.7 
+ 20.1 
+ 20.5 
+ 20.9 
+ 21.2 

+ 21.9 
+ 22.5 
+ 23.0 
+ 23.4 
+ 23.7 

©co©t»© 

Tp Tp ^p Tp ^P 

CM CM CM CM CM 

f-h CM © t'- 00 

© © © © © 
CM CM CM CM CM 

+ 26.0 
+ 26.1 

Mean ele¬ 
vation of 
compart¬ 
ment, 
in feet 

100 

200 

300 

400 

500 

600 

700 

800 

900 

1 000 

1 100 

1 200 

1 300 

1 400 

1 500 

1 600 

1 700 

1 800 

1 900 

2 000 

2 200 

2 400 
2 600 
2 800 

3 000 

3 200 
3 400 
3 600 

3 800 

4 000 

4 500 

5 000 

5 500 

6 000 
6 500 

7 000 

7 500 

8 000 

8 500 

9 000 

9 500 
10 000 
11 000 
12 000 
13 000 

14 000 

15 000 





































Zone D 2 . 

[Inner radius, 380 meters; outer radius, 590 meters. Six compartments.] 


14 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 





1600 

feet 




CO tp © © © 
04 04 04 04 04 

1 1 1 1 1 

© © TP CO CO 
04 04 04 04 04 

1 1 1 1 1 

04 h O © © 
04 04 04 h ih 

II II 1 

|>i © © © tp 

77777 

TP Tp co X X 

77777 

X X 04 04 04 

IH iH rH rH rH 

Mill 

04 04 

rH rH 

1 1 




J09 J 

oosi 



04 

04 

1 

04 CO CO -rf ■'T 
04 04 04 04 04 

1 1 1 1 1 

TP CO 04 04 1-H 
04 04 04 04 04 

II 1 II 

OOOOCON 

04 H rH H rH 

II II 1 

© © Tp X X 

77777 

X X 04 04 04 

IH rH rH iH iH 

Mill 

04 04 H H H 

1-H 1-H 1—4 r-4 1—1 

Mill 

rH rH 
rH rH 

1 1 




1400 

feet 



l l 

H 04 04 04 04 
04 04 04 04 04 

1 1 1 1 1 

04 i-l H O © 
04 04.04 04 rH 

I Fll 1 

x x © © 

77777 

© tP X 04 04 

iH rH H rH rH 

M M 1 

04HHHH 

77777 

HHHOO 
1—4 rH rH H rH 

Mill 

© © 
rH rH 

1 1 




1300 

feet 



CO © © 

f-4 »-H 04 

1 1 1 

© © © rH © 

04 04 04 04 04 

1 1 II 1 

OOOOCN 

04 H H H H 

II II 1 

|H CO © © TP 

77777 

X 04 04 H rH 

iH rH r-l iH rH 

II II 1 

HCCO© 

77777 

© © © © © 
77 ii i 

© © 

1 1 




1200 

feet 



© r- oo oo 

7777 

© © © © © 
77777 

oo x o- © © 

77777 

© TP TP CO CO 

77777 

04 iH rH © O 

iH rH rH rH rH 

M M 1 

© ©©©© 
7 ii i i 

©©XXX 

Mill 

XX 

1 1 




1100 

feet 



tp © © © t*. 

1-4 H i—4 rH H 

1 1 1 1 1 

t'-t'-L-C'-l'- 

77777 

© © © TP HP 

77777 

X CO 04 04 h 

77777 

rH © © © © 

77 m i 

XXXXX 

1 II II 

x x x r-o- 

Mill 

O-tn 

1 1 



4-3 

1000 

feet 


04 

7 

X —T Tp © © 

77777 

© © © © © 
77777 

Tp TP CO CO 04 

77777 

NhhoO 

77777 

© ©x x x 

II II 1 

tn i>i r>. r- 

II II 1 

t^t^r»©© 

II II 1 

© © 

1 1 



© 

s 

-e 

900 

feet 


© 1-4 

77 

04 CO CO CO CO 

77777 

CO CO CO CO CO 

iH H i—( r—< 1-H 

1 1 II 1 

CO 04 rH H O 

77777 

© © © © © 
77 m i 

X XO-O-L- 

II II 1 

© © © © © 

ii ii i 

CO © © © © 

II II 1 

© © 

1 1 



CL 

S 

O 

800 

feet 


©©© 

1—4 

1 1 1 

—4 i-4 i-i 04 04 

77777 

04 04 04 rH rH 
rH rH rH rH iH 

1 1 1 II 

!-<©©©© 
777 i i 

XXXNN 

II II 1 

t"T © © © © 

M M l 

© © © © © 

ii ii i 

© © © © Tp 

II II 1 

TP Tp 

1 1 



£ 

700 

feet 


C^OCQCO 

Mil 

© © © © © 

17777 

© © © © © 

• 7777 i 

© X OOOON 

1 II II 

t>- 0- © © © 

II II 1 

© © © © Tp 

M M 1 

Tp Tp Tp Tp Tp 

II II 1 

Tp Tp ^P Tp Tp 

II II 1 

TP TP 

1 1 



« 

600 

feet 


© © o- r- oo 

1 1 1 1 1 

00 00 00 00 00 

1 1 1 1 1 

00 00 00 00 00 

1 1 1 1 1 

o- f>. i - © © 

II II 1 

CO © © © © 

II M 1 

TP Tp TP TP TP 

M II 1 

XXXXX 

II II 1 

XXXXX 

II II 1 

XX 

1 1 




500 

feet 

T 

1 1 1 1 1 

©NNNN 

1 1 1 II 

© © © © © 

1 1 II 1 

CO © © © Tp 

II 1 1 1 

TP TP TP Tp TP 

1 1 1 1 1 

XXXXX 

II II 1 

04 04 04 04 04 

II II 1 

04 04 04 04 04 

II II 1 

04 04 

1 1 




400 

feet 

04 CO 

1 1 

rr if if »D O 

1 1 1 1 1 

IO LO lO lO »o 

1 1 1 1 1 

© © © tp tp 

1 1 1 1 1 

TP Tp Tp CO CO 

1 1 1 1 1 

X X X X X 

II II 1 

04 04 04 04 04 

II II 1 

04 04 04 04 04 

II II 1 

1-H i-H rH i-H 1—4 

II II 1 

77 

1 



g ® 

tH 04 04 

CO CO CO CO CO 


CO CO CO CO CO 

CO CO 04 04 04 

04 04 04 04 04 

04 H H H H 

iH iH iH rH rH 

rH rH rH rH rH 

rH rH 





1 1 1 

1 1 1 1 1 

i i ii i 

1 1 II 1 

1 II 1 1 

1 1 1 1 1 

M M 1 

II II 1 

II II 1 

1 1 

03 



g® 

H H H »H 

04 04 04 04 04 

04 04 04 04 04 

04 04 04 04 04 

04 04 i—< iH i—4 

HHHHH 

iH iH iH iH rH 

iH © © © © 

©©©©© 

©© 

«*H 




1 1 1 1 

Mill 

1 1 1 1 1 

1 1 1 1 1 

1 1 1 1 1 

1 1 1 1 1 

M M 1 

1 



a 

.2 



100 

feet 

O © © rH rH 

1 1 

1—4 1—4 1—4 1—4 1—4 

1 1 1 1 1 

i—4 1—4 1—4 1—4 rH 

1 1 1 1 1 

t—f H H H rH 

1 1 1 1 1 

iH rH rH iH rH 

1 1 1 1 1 

HOOOO 

1 

©©©©© 

©OOO© 

©O©©© 

©© 

> 

<D 



1600 

feet 

*-h 1-1 04 04 04 

+ + + + + 

04 04 04i-4i-4 

+ + + + + 

1-4 © © 1-4 1-4 

+ 1 1 

04 04 CO CO CO 

1 1 1 1 1 

TP © © © © 

II II 1 

trNNXX 

Mill 

X©©©© 

rH rH 

II II 1 

©ooo© 

77777 

rH rH rH rH rH 

77777 

rH rH 
iH rH 

1 1 

o 

V-t 

a 

O 



1500 

feet 

i-l rH 04 04 04 

+ + + + + 

04 04 04 04 i-4 

4- + + + + 

i—4 i—4 © © i-4 

+ + 1 

iH 04 04 04 CO 

1 1 1 1 1 

CO TP © © © 

II II 1 

©©f'-t'-t'- 

II II 1 

X X X © © 

II II 1 

© © © © © 
ii 177 

© © © © © 
77777 

© © 
rH rH 

1 1 

+2 

i 



1400 

feet 

1—H 1-4 04 04 04 

H — 1 — i — 1 — H 

04 04 04 04 04 
+ + + + + 

1—4 r-4 © © © 
+ + 

iH rH rH 04 04 

Mill 

CO CO TP TP © 

II II 1 

© © © © © 

1 1 1 1 1 

r- !>• x x x 
II II 1 

x © © © © 

ii ii i 

© © © © © 
M M i 

© © 

1 1 

a 



1300 

feet 

T-4 04 04 04 04 
+ + + + + 

04 04 04 04 04 
+ + + + + 

04 1-4 1—4 © © 

+ + + 

© H H H 04 

II II 

04 CO CO tp tp 

II II 1 

© © © © © 

1 1 1 1 1 

©ir-t^rroo 

Mill 

XXXXX 

II II 1 

xxxxx 
II II 1 

X X 

1 1 




1200 

feet 

i-4 04 04 04 CO 
+ + + + + 

CO CO CO 04 04 
+ + + + + 

04 04i-4i-4© 
+ + + + 

COhhh 

1 1 1 

04 04 COCO tp 

II II 1 

Tp Tp © © © 

1 1 1 1 1 

© © © © 0- 
II II 1 

tr. t>. t>r 

II II 1 

IT. tr. 

II II 1 

L- U- 
1 1 




1100 

feet 

1-4 04 04 CO CO 
+ + + + + 

CO COCO CO 04 
+ + + + + 

04 04 04 i-« i-4 

4“ + + + + 

iH © © iH iH 
+ 1 1 

rH 04 04 COCO 

II 1 II 

X Tp TP Tp Tp 

II II 1 

© © © © © 
MM! 

© © © © © 
II II 1 

© © © © £- 
II II 1 

1 1 



4-3 

© 

1000 
feet ! 

i-4 04 04 CO CO 
+ + + + + 

CO CO CO CO CO 
+++++ 

04 04 04 04 i-4 
+ + + + + 

hhOOO 

+ + 

iH rH 04 04 04 

II II 1 

X X X X TP 

II II 1 

Tp Tp © © © 

II II 1 

© © © © © 
II II 1 

© © © CO © 

II II 1 

© © 

1 1 



B 

■e 

s 

a 

900 

feet 

i-4 04 04 COCO 

4- + + + + 

CO CO CO CO CO 

CO 04 04 04 04 

hhhhO 

+ +++ 

©HHHOI 

1111 

04 04 04 X X 

II II 1 

X X Tp Tp Tp 

II II 1 

TP Tp Tp Tp Tp 

II II 1 

© © © © © 
II II 1 

© © 

1 1 



s 

o 

© 

© 

800 

feet 

i-4 04 04 CO CO 
+ + + + + 

CO CO CO CO CO 

CO CO 04 04 04 
+ + + + + 

04HHHH 

+ + + + + 

© © © H H 

1 1 

rH 04 04 04 04 

II II 1 

04 X X X X 

II II 1 

X X Tp TP TP 

II II 1 

TP Tp Tp Tp Tp 

II II 1 

Tp TP 

1 1 



> 

o 

iQ 

700 

feet 

1-4 1-4 04 04 CO 

CO CO CO CO CO 
+ + + + + 

CO CO 04 04 04 
+ + + + + 

04 04HHH 
+ + +++ 

HOOOO 

+ 

HHHHC4 

II 1 II 

04 04 04 04 X 

II II 1 

xxxxx 
II II 1 

CO CO X X X 

1 II II 

XX 

1 1 




600 

feet 

1-4 1-4 04 04 CO 
+ + + + + 

CO CO CO CO CO 

CO CO CO 04 04 
+ + + + + 

04 04 04 rH rH 
+ + + + + 

HHOOO 

++ 

© o HHH 

i 1 1 

IH iH 04 04 04 

II II 1 

04 04 04 04 04 

II II 1 

04 04 04 04 04 

II II 1 

04 04 

1 1 




500 

feet 

1-4 1-4 04 04 04 

CO CO CO CO CO 

CO CO 04 04 04 

04 04 04 04 H 

HHHOO 
+ + + 

ooo©o 

iH HHHH 

II II 1 

77777 

04 04 04 04 04 

1 II II 

04 04 

1 1 




400 

feet 

rH rH 04 04 04 
+ + + + + 

C4 04 CO CO CO 
+ + + + + 

04 04 04 04 04 
+ + + + + 

04 04 04 04 04 
+ + + + + 

+ + + + + 

©ooo© 

OOOHH 

1 1 

HHHHH 

II II 1 

77777 

rH rH 

1 1 




300 

feet 

OHHC4C4 
+ + + + 

04 04 04 04 04 

04 04 04 04 04 

+ + + 4- + 

04 04 04 ih iH 
+ + + + + 

iH iH HHH 

+ + + + + 

HOOOO 

+ 

© © © © © 

©©©©© 

OHHHH 

II II 

rH rH 

1 1 




200 

feet 

o t-4 ^4 1—4 1-4 
+ + + + 

1-4 1-4 04 04 04 
+ + + + + 

04 04 04 i—l i—i 

iH H H H H 

+ + + + + 

HHHHH 

+ + + + + 

IH © © o © 

+ 

©OOO© 

©©©©© 

©©©o© 

©© 




100 

feet 

OOOHH 

+ + 

rH i—4 i—4 rH 1—4 

+ + + + + 

rH rH i—1 rH rH 

H H H iH rH 

+ + + + + 

HHOOO 
+ + 

©ooo© 

©©©©© 

©©©©© 

©o©o© 

©© 

i 


Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

O © 1-4 1-4 04 

+++ 

XXtP©© 

+++++ 

O- GO © © H 

+++77 

04 04 CO TP © 
rH rH rH iH rH 

+ + + + + 

© tr. © © IH 

H H rH 04 04 

+ + + + + 

rH 04 X Tp TP 

04 04 04 04 04 

+ + + + + 

© r*- x © © 

04 04 04 04 04 
+ + + + + 

©Ohhh 

XXXXX 

+ + + + + 

04 04 04 X X 
XXXXX 

+ 33 
+33 

«S 

c 

O 

+2 

I 

Com¬ 

pensa¬ 

tion 

© ©OO© 

© © © © © 

©©©©© 

© © © © © 

o © © © o 

© © © © © 

© rH rH iH iH 

III! 

*H rH iH iH rH 

II II 1 

iH HHH rH 

II 1 II 

rH 04 

1 1 

C 

o 



Wit-. 

1-4 CO 04 © 

© 'U* CO 04 04 

rH rH © © 00 

O- © TP 04 © 

CO © X © © 

X © Tp H t - *— 

H XX04 © 

©©©©TP 

t^© © © Tp 

X rH 

O 



CL Cm 
§2 

© © © r-4 1-4 

+ + + + + 

04 X TP © © 

+ + + + + 

0* X © © © 

+ + + + + 

*H 04 CO tp tP 

iH iH rH iH rH 

+ + + + + 

©noo©6 

ih rH H H 04 
+ + + + + 

rH 04 CO Tp ip 

04 04 04 04 04 
+ + + + + 

© x © gi 

04 04 04 04 04 

+ + + + + 

O rH rH 04 04 
XXXXX 

+ + + + + 

04 X X Tp TP 
XXXXX 

+++++ 

X X 
++ 


iota 

© fl 03 . ^ 

88888 
i-4 04 CO tp © 

© ©©©© 
o o © © © 

©I> X © © 

OCOQQ 
© © © © © 
rH 04 CO tp © 

88888 
© 4^ X © © 

88888 

04 tp ?£> x © 

88888 

04 tp © X © 

©OOO© 

88888 

© © © © © 
© © © © © 
© © © © © 

|H!i 

li 


a 

3 

•■Spi® 

C © • 

tss 


1-4 

HHHHH 

HHHH04 

04 04 04 04 CO 

XXXXtp 

TP©©©© 

hhOOQOO) 

© © h 04 X 

ih rH rH rH 

Tp © 

HH rH 

1 
















































































[Inner radius, 590 meters; outer radius, 870 meters. Eight compartments.] 


INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


15 




2600 

feet 



© © !"- 
CM CM CM 

1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

© CO CM rH © 
CM CM CM CM rH 

1 1 1 1 1 

05 00 ^ r- © 
rH rH 1—4 1—4 rH 

1 1 1 1 1 

© © © Ht 1 HJi 

rH H rH rH 1—4 

1 1 1 1 1 

Mi CO 

1—4 rH 

1 1 



2400 

feet 



CO M* to to 
CM CM CM CM 

1 1 1 1 

© © © If 

CM CM CM CM CM 

1 1 1 1 1 

CM rH © © 00 
CM CM CM rH i-4 

1 1 1 1 1 

© © © © 

rH rH i—4 rH i—4 

1 1 1 I 1 

M< Mi CO CO CO 

77777 

CM CM 

1-4 rH 

1 1 



2200 

feet 



rH CM CO CO CO 
CM CM CM CM CM 

1 1 1 1 1 

CO CO CM CM CM 
CM CM CM CM CM 

1 1 1 1 1 

© © oo r- © 

CM 1 -H rH rH rH 

1 1 1 1 1 

© Mi M 1 CO CO 

1—4 1—4 1—4 1—4 1—4 

1 1 1 1 1 

CO CM CM CM rH 

77777 

r4 rH 
rH rH 

1 1 



2000 

feet 


00 

7 

© © 1—4 1—4 1—4 

H CM CM CM CM 

1 II 1 1 

S § § § 2 

1 1 1 1 1 

00 t'- © © M* 

i—4 rH 1—4 1—4 i—4 

1 1 1 1 1 

CO CO CM CM CM 

rH i—1 rH i—4 i—4 

1 1 1 1 1 

HHH©© 
1—4 1—4 i—4 i—4 rH 

1 1 1 1 1 

©© 
rH rH 

1 1 



1800 

feet 


© 

1—4 1—4 

1 1 

00 00 © © © 
77777 

OOOONNN 

1—4 i—4 1—4 1—4 1—4 

1 1 1 1 1 

© Mi CO CO CM 

77777 

CM 1-4 rH©© 

77777 

© © © © © 
77 i i i 

©00 

1 1 


S 

a 

t; 

1600 

feet 


CO M4 © 

i—1 i—• 1—4 

1 1 1 

© © © © © 
77777 

© © © © Tf 
i—4 i—4 HHH 

1 1 1 1 1 

CO CM rH rH © 
rH rH rH rH rH 

1 1 1 1 1 

© © 05 © 05 

7 i i i i 

00 00 00 00 f- 

1 1 1 1 1 

1 1 


<3 

a 

a 

o 

1400 

feet 


*—4 CM CO CO 

7777 

rr M< Tf4 Tt< M* 
i—4 rH 1—4 i—4 1—4 

1 1 1 1 1 

CO CO CO CM CM 

77777 

1-4 © © ©00 

777 i i 

oo oo *•- 

1 1 1 1 1 

i>. r- © © © 

i i i i i 

© © 

1 1 


* 

« 

1200 

feet 


OOOHH 
1—4 rH i—4 *—4 

1 1 1 1 1 

CM CM CM i-4 i-4 

77777 

1-4 © © © © 

77777 

©oooor^r- 

1 1 1 1 1 

© © © © © 

i i i i i 

© © © © © 

i i i i i 

©© 

1 1 


1000 

feet 

© 

1 

r-oo©©© 

1 1 1 1 1 

© © © © © 

11111 

oo oo oooo r- 

II 1 1 1 

© © © © 

1 1 II 1 

© © Ht4 M< M4 

1 1 1 1 1 

M4M4M4M4M4 

1 1 1 1 1 

coco 

1 1 



800 

feet 

m« 

1 1 

© ©i>r^i>. 

1 1 1 1 1 

r- © 

Mill 

© © © © © 

i i i i i 

© © M4 M4 M4 

1 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO CO CM CM CM 

1 1 1 1 1 

CM CM 

1 1 

1 

a 

,o 


600 

feet 

1 1 1 

M< © © © © 

1 1 1 1 1 

© © © © hji 

i i i i i 

M< M< M 1 M* M< 

1 1 1 1 1 

CO CO CO CO CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

1—4 rH 

1 1 

Cj 

4-i 

CO 

In 

O 


400 

feet 

1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO coco CO CO 

1 1 1 1 1 

CO CM CM CM CM 

1 1 1 1 1 

CM CM CM i—i rH 

1 1 1 1 1 

i—4 1—4 rH rH rH 

1 1 1 1 1 

rH rH i—4 rH rH 

1 1 1 1 1 

1—4 rH 

1 1 

§ 

hh 

C8 

> 


200 

feet 

© rH i—l i—( rH 

1 1 1 1 

77777 

77777 

rH i—4 t—1 i—4 t—4 

1 1 1 1 1 

rH rH rH rH rH 

1 1 1 1 1 

© © © © © 

© © © © © 

©© 

*H 

o 

«n 


2600 

feet 

+ + + + + 

rH t—4 O © *-4 

+ + 1 

i—( CM CO CO M« 

1 1 1 1 1 

Tf © © © © 

1 1 1 1 1 

t- r- oo © © 

1 1 1 1 1 

05©©©© 

17777 

Ohhhh 

77777 

Ti¬ 

ll- 

fl 

# o 

HH> 

o 

© 


2400 

feet 

l 

+ + + + + 

CM 1-4 1-4©© 

+ + + 

*-41-4 CM CO CO 

Mill 

M* M 1 M* © © 

1 1 1 1 1 

© f- 00 00 

1 1 1 1 1 

00 © © 05 © 

1 1 1 1 1 

© o © © © 

rH i—4 i—4 r—4 

Mill 

© © 
rH rH 

1 1 

b 

o 

o 


2200 

feet 

+ + + + + 

CM CM i-41-4© 
+ + + + 

© rH i-4 CM CM 

II II 

CO CO Mi 1+ Th 

1 1 1 1 1 

© © © 

1 1 1 1 1 

r- oo oo oo oo 

i i i i i 

00 © © © © 

1 1 1 1 1 

© © 

1 1 



2000 

feet 

HINNCOCO 

CM CM CM i-4 i-4 
+ + + + + 

O © 1—4 1-4 CM 

1 1 1 

CM CO CO CO Mi 

1 1 1 1 1 

© © © © 

1 1 1 1 1 

© r—r— r— 

1 1 1 1 1 

r- oo oo oo oo 

1 1 1 1 1 

00 00 

1 1 



1800 

feet 

rH CM CM CO CO 

CO CM CM CM 1-4 

1-4 © © 1-4 1—4 
+ 1 1 

i-4 CM CM CM CO 

1 1 1 1 1 

CO M* M" © © 

1 1 1 1 1 

© © © © © 
i i i i i 

© © r-r- 
1 1 1 1 1 

t>- r— 

1 1 


fl 

© 

a 

t, 

1600 

feet 

rH CM CO CO CO 
+++++ 

CO CO CM CM CM 
+ + + + + 

hhh 00 
+ + + 

© 1—4 1—4 1—1 CM 

1 1 1 1 

CM CO CO CO M 1 

1 1 1 1 1 

M4 M* © © © 

I 1 1 1 1 

© © © © © 
i i i i i 

© © 

1 1 


c3 

ft 

a 

© 

1400 

feet 

1-4 CM CO CO CO 
+ + + + + 

CO CO CO CM CM 
+ + + + + 

CM HHH© 
+ + + + 

©©HHH 

1 1 1 

CM CM CO CO CO 

1 II 1 1 

CO Mi Mi Mi M4 

1 1 1 1 1 

M* Mi M* © © 

1 1 1 1 1 

© © 
i i 


© 

> 

o 

1© 

1200 

feet 

rH CM CO CO CO 
+++++ 

CO CO CO CO CM 

CM CM rH i-4 © 
+ + + + 

©©©©© 

rH rH CM CM CM 

1 1 I 1 1 

CM CO CO CO CO 

1 1 1 1 1 

CO CO CO CO Ml 

1 1 1 1 1 

Mi M“ 

1 1 



1000 

feet 

1-4 CM CM CO CO 
+ + + + + 

CO CO CO CO CO 
+ + + + + 

CM CM CM i-t i-( 
+ + + + + 

HHOOC 
+ + 

© rH 1—4 1—4 1—4 

1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CM CM CM CO 

1 1 1 1 1 

CO CO 

1 1 



800 

feet 

i-4 CM CM CO CO 
+ + + + + 

CO CO CO CO CO 
+++++ 

CM CM CM CM i-4 
+ + + + + 

rH i-4 i—4 i—4 rH 

+ + + + + 

OOOHH 

1 1 

77777 

rH rH rH CM CM 

1 1 1 1 1 

CM CM 

1 1 



600 

feet 

i—l i—4 CM CM CM 
+ + + + + 

CO CO CO CM CM 
+++ + + 

CM CM CM CM CM 
+ + + + + 

1—4 1—4 1—4 rH 1—4 
+ + + + + 

rH© ©©© 
+ 

© © © rH rH 

1 1 

i—4 i—4 rH rH i—4 

1 1 1 1 1 

r4 rH 

1 1 



400 

feet 

1-11-4 1-4 CM CM 

+ + 4- + + 

CM CM CM CM CM 
+ + + + + 

CM CM CM i-i i-i 
+ + + + + 

i—l i—< rH 1—4 1-4 

+ + + + + 

rH©©©© 

+ 

©©©©© 

©OOO© 

o© 



200 

feet 

OHHHH 

+ + + + 

1—4 1—4 1—4 »-4 i—4 

+ + + + + 

+ + + + + 

rH rH •—4 i—4 i—4 

+ + + + + 

© © © © © 

©©©O© 

©©©©© 

©© 

i 

Topog¬ 

raphy 

and 

compen¬ 

sation 

© TH iH cm CO 

++++ 

TJ4 © 00 © 

+ + + + + 

© i-i CM -f © 

+7+77 

© © t>- 00 © 

rH 1—4 rH rH rH 

+20 
+22 
+ 23 
+ 24 
+ 25 

©©1^ 00 00 
CM CM CM CM CM 

+ + + + + 

© © © © 1-4 
O* 0* CO CO CO 

+++++ 

+31 
+ 31 

U-H 

fl 

.2 

o 

© 

Com- 

pensa- 

tion 

©ooo© 

©©©O© 

©©©©© 

o©oo© 

© hH rH 1-4 rH 

1 I 1 1 

1—4 rH 1—4 1—4 1—4 

1 1 1 1 1 

1—4 rH 1—4 rH 1—4 

1 1 1 1 1 

rH CM 

1 1 

b 

o 

o 

Topog¬ 

raphy 

+ 0.1 
+ 0.6 
+ 1.2 
+ 2.1 
+ 3.1 

co©r-©CM 

m» © co oo © 

+ + + + + 

+ 10.5 
+ 11.6 
+ 12.8 
+ 13.8 
+ 14.8 

00 T- © Ml 1—4 

© ©t7 oo 05 

1—4 rH 1—4 rH rH 

+ + + + + 

+ 20.8 
+22.3 
+23.6 
+ 24.7 
+25.7 

+ 26.5 
+ 27.3 
+28.0 
+28.6 
+29.1 

+29.6 
+30.0 
+ 30.8 
+ 31.5 
+32.1 

+32.6 

+33.0 


Mean eleva¬ 
tion of com¬ 
partment, 

s 

4-4 

200 

400 

600 

800 

1 000 

1 200 

1 400 

1 600 

1 800 

2 000 

2 200 

2 400 

2 600 

2 800 

3 000 

3 200 

3 400 

3 600 

3 800 

4 000 

ggggg 
© © © © © 

© © © © 

7 000 

7 500 

8 000 

8 500 

9 000 

9 500 
10 000 
11 000 
12 000 
13 000 

14 000 

15 000 














































16 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 



o 

N 


■52 


C3 

ft 

a 

o 


A 

.a 3 

S 


o 

X 

CM 


*d 

c3 





3200 

feet 




©H CM CO CO 
CO CO CO CO CO 

1 II 1 1 

CO CO CO CO CO 
CO CO CO CO CO 

1 1 1 1 1 

CO CM CM rH H 
CO CO CO CO CO 

1 1 1 1 1 

© oo © Ht4 
CM CM CM CM CM 

1 1 1 1 1 

■^4 CO CM rH © 

CM CM CM CM CM 

1 1 1 1 1 

© 00 00 

H H H 

1 1 1 




3000 

feet 



8 

l 

fl>©OHH 
CM CO CO CO CO 

1 1 1 1 1 

rH rH rH rH rH 

CO CO CO CO CO 

II II 1 

© © © © CO 
CO CO CM CM CM 

1 1 1 1 1 

© Ht* co cm 

CM CM CM CM CM 

1 1 1 1 1 

CM H © © CO 
CM CM CM h h 

1 1 1 1 1 

P- P- © 

777 




2800 

feet 



© © 
CM CM 

1 1 

P- 00 OC © © 
CM CM C^.*M CM 

1 1 1 1 1 

II II 1 

oo p- r^. co co 

CM CM CM CM CM 

1 1 1 1 1 

© CO CM H © 
CM CM CM CM CM 

1 1 1 1 1 

©©oor^r- 

CM H H H H 

1 1 1 1 1 

© © © 

rH H H 

1 1 1 




2600 

feet 



CO if © 
CM CM CM 

1 1 1 

© co co p- p^ 

CM CM CM CM CM 

1 1 1 1 1 

1^- © © © © 
CM CM CM CM CM 

1 1 1 1 1 

© © if if CO 
CM CM CM CM CM 

1 1 1 1 1 

CM rH ©© 00 
CM CM CM h h 

1 II 1 1 

00 tr N © © 

77777 

It4 CO 

777 




2400 

feet 



© ft CM CO 
CM CM CM CM 

1 1 1 1 

if if if if if 
CM CM CM CM CM 

1 1 1 1 1 

if if if CO CO 
CM CM CM CM CM 

1 1 1 1 1 

CO CM CM H H 
CM CM CM CM CM 

II 1 1 1 

©©oot^r>- 

CM H H H H 

1 1 1 1 1 

© © © H*4 CO 

77777 

CO CM CM 

rH H H 

1 1 1 




2200 

feet 



00 © © r-4 H 
H rH CM CM CM 

1 II 1 1 

CM CM CM CM CM 
CM CM CM CM CM 

1 1 1 1 1 

CM CM rH rH rH 
CM CM CM CM CM 

1 1 1 1 1 

§§222 

1 1 1 1 1 

oo © © © 

77777 

■4*4 T*4 CO CM CM 

77777 

777 



§ 

a 

t 

03 

ft 

2000 

feet 


© 

7 

© p- co © © 

77777 

2 § 3 § § 
l 1 1 l 1 

© © © oo oo 

77777 

oo r^. © 

HHHHH 

1 1 1 1 1 

© © Hf CO CO 

HHHHH 

CM CM h h © 

77777 

© © © 

7 i i 



1800 

feet 


CO if 

rH H 

1 1 

© co co p- 

77777 

r>- p- p- p- p* 

HHHHH 

Mill 

r*N©©© 

HHHHH 

1 1 1 1 1 

© © © if if 

77777 

CO CO CM CM H 

77777 

H © ©05 © 

777 i i 

00 00 00 

1 1 1 



a 

o 

o 

£ 

1600 

feet 


H CM CM 

777 

CO if if © © 

77777 

© © © © © 
77777 

if if if if CO 

77777 

CO CO CM CM CM 

H H H H H 

II 1 II 

H H © © © 
H H H H 

1 1 1 1 1 

©©oocor- 

1 1 1 1 1 

r>» P- 

i i i 



o 

'S 

1400 

feet 


00 © © h 

H r—4 

1 1 1 1 

CM CM CM CO CO 

rH H rH H rH 

1 1 1 1 1 

CO CO CO CO CM 

77777 

CM CM CM rH rH 

77777 

H H © © © 

77777 

© © 00 00 00 

1 1 1 1 1 

© © 

1 1 1 1 1 

© © © | 

1 1 1 




1200 

feet 


© oo © © 

1 1 1 1 1 

©©©*-4 1-4 

77777 

*-4 *H © © © 
H rH rH rH rH 

Mill 

© © © © © 
77 i i i 

© © co co 00 

1 1 1 1 1 

t>. rr. © © 

1 1 1 1 1 

© © © © © 

i i i i i 

1*4 1*4 1*4 

1 1 1 




1000 

feet 

1*4 

1 

©COf^t^OO 

1 1 1 1 1 

CO 00 00 00 CO 

1 1 1 1 1 

00 00 00 00 00 

1 1 II 1 

co c© r- p- 
1 1 1 1 1 

p- f>. p- © © 

1 1 1 1 1 

© © © © © 
i i i i i 

TJ4 *St4 H*4 rf4 T*4 

I 1 1 1 1 

CO CO CO 

1 1 1 

1 



800 
j feet 

CO ^ 

1 1 

if to © © CO 

1 1 1 1 1 

© © © © © 

1 1 1 1 1 

© © © © © 
II II 1 

© © © © © 
i i i i i 

© © © © © 
i i i i i 

TJ4 Ht* Tt4 Tf4 CO 

1 1 1 1 1 

CO CO CO CO CM 

1 1 1 1 1 

CM CM CM 

1 1 1 

B 

jo 

’•*3 

$ 

CO 

•m 

o 



600 

feet 

CM CM CO 

1 1 1 

CO if if if if 

II 1 1 1 

If © © © © 

1 1 1 1 I 

© if if if if 

1 1 1 1 1 

r}4 rf rf 

1 1 1 1 1 

if CO CO CO CO 

1 1 1 1 1 

CO CO CO CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

H H rH 

1 1 1 



400 

feet 

HHHN 

I 1 1 1 

CM CM CM CO CO 

1 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CM CM H H H 

1 1 1 1 1 

77777 

777 

B 

_o 

53 

p3 



200 

feet 

O O H H H 

1 1 1 

77777 

77777 

77777 

77777' 

77777 

77777 

H © © © © 

1 

© © © 

CP 

in 



3200 

feet 

iHNCOCOCO 

+++++ 

CO CO CO CO CO 

+ + + + + 

CM CM *-4 rH © 

+ + + + 

©rH rH CM CM 

1 1 1 1 

CO CO if if © 

1 1 1 / 1 

© © © © © 

1 1 1 1 1 

r-oooo©© 

1 1 1 1 1 

© © © H H 

77777 

CM CM CM 

777 

*2 

a 

o 



3000 

feet 

H CM CO CO if 

+++++ 

if if if CO CO 

+ + + + + 

CO CM CM *H *H 

© ©rH rH CM 

1 1 1 

CM CO CO CO if 

1 1 1 1 1 

if © © © © 

1 1 1 1 1 

©t^tHOOOO 

1 1 1 1 1 

© © © © © 
i i 177 

in 

-ii 

o 

0) 

e 

o 



2800 

feet 

h CM CO CO if 

+++++ 

if if If if CO 

+ + + + + 

CO CO CM CM rH 

+ + + + + 

rH © © rH rH 

+ 1 1 

rH CM CM CO CO 

1 1 1 1 1 

CO -4*4 if if © 

1 1 1 1 1 

© © tn 

1 1 1 1 1 

co co oo © © 

1 1 1 1 1 

© © © 
777 

O 



2600 

feet 

H CM CO CO if 

if if if if if 
+ + + + + 

CO CO CO CM CM 

rH rH © © © 

+ + 

rH rH CM CM CM 

1 1 1 1 1 

CO CO CO if if 

1 1 II 1 

© © © © fr 

1 1 1 1 1 

T'- P- L- CO OO 

1 1 1 1 1 

© © © 

111 




2400 

feet 

1-H C^CO CO 

if if if if if 
++ + + + 

if CO CO CO CM 

+ 4-4- + + 

CM rH H rH O 
+ + + + 

OH H H CM 

1 1 1 1 

CM CM CO CO CO 

1 1 1 1 1 

Tf4 Tf4 © © © 

1 1 1 1 1 

© © © r>» 

1 1 1 1 1 

00 00 00 

1 1 1 




2200 

feet 

r-4^CO 

If if if if if 
+ + + + + 

if if co CO CO 
+++++ 

CM CM rH rH H 
+ + + + + 

© © © H H 

1 1 

H CM CM CM CM 

Mill 

CO CO "*4 t#4 © 

1 1 1 II 

© © © © © 
i i i i i 

Pi* P- 

1 1 1 



fl 

9 

a 

2000 

feet 

h CM CO if if 
+ + + + + 

if if © © if 

•<#4 if if CO CO 
+++++ 

CO CM CM CM ^ 

H H © © © 

+ + 

hhhhCM 

1 1 1 1 1 

CM CO CO CO Tt* 

1 1 II 1 

H*4 TJ4 © © © 

1 1 1 1 1 

© © © 

1 1 1 



■4-3 

h* 

C3 

ft 

a 

o 

9 

9 

1800 

feet 

H (NCO 
+++++ 

if to © to © 

if If Tt* if CO 
+ + + + + 

CO CO CM CM CM 
+ + + + + 

HHHHO 

++++ 

© © ©H H 

1 1 

H CM CM CO CO 

1 1 1 1 1 

CO CO Tt4 rf4 TJ4 

1 I 1 1 1 

1*4 © © 

1 1 1 



1600 

feet 

iHNCOrf 
+ + + + + 

if if © © © 
+++ + + 

if if if if 

CO CO CO CM CM 
+ + + + + 

CM CM H H H 
+++++ 

H ©©©© 

+ 

H H H CM CM 

1 1 1 1 1 

CM CO CO CO CO 

1 1 1 1 1 

*4*4 1*4 1*4 

1 1 1 



O 

rQ 

1400 

feet 

HNCOCO^ 

+++++ 

if if if © If 
+ + + + + 

If If If If If 
+ + + + + 

CO CO CO CO CM 
+ + + + + 

CM CM CM H h 
+ + + + + 

hhhOO 
+ + + 

H H H 

II 1 1 

CM CM CM CM CM 

1 1 1 1 1 

CO CO CO 

1 1 1 




1200 

feet 

C^CO CO 

if if if if if 

if if ^ if if 
+ + + + + 

CO CO CO CO CO 
+++++ 

CM CM CM CM CM 
+ + + + + 

H H H H H 

+ + + + + 

© © © ©H 

1 

H H H H CM 

1 II 1 1 

CM CM CM 

1 1 1 




1000 

feet 

H CM CM CO CO 
+ + + + + 

co ^ 77 + 

If if rf if If 

CO CO CO CO CO 
+++++ 

CM CM CM CM CM 
+ + + + + 

CM H H H H 
+ + + + + 

rH ©©©© 

+ 

© H H H H 

1 II 1 

H H H 

1 1 1 




800 

feet 

h h CM CM CO 
+ + + + + 

CO CO CO if if 

if co co co co 
+ + + + + 

CO CO CO CO CO 
+++++ 

CM CM CM CM CM 
+ + + + + 

CM CM CM h H 
+ + + + + 

H H H © © 

+ + + 

©©©©rH 

1 

777 




600 

feet 

H H rH CM CM 
+ + + + + 

CM CO CO CO CO 
+ + + + + 

CO CO CO CO CO 
+++++ 

CO CO CM CM CM 
+ + + + + 

CM CM CM CM CM 
+ + + + + 

CM CM CM H H 
+ + + + + 

H H H H © 
+ + + + 

OO©©© 

© © © 




400 

feet 

Oh h h CM 
+ + + + 

CM CM CM CM CM 
+ + + + + 

CM CM CM CM CM 

CM CM CM CM CM 
+ + + + + 

CM CM H H H 
++++ + 

+ + + + + 

H H H H © 
+ + + + 

©©©©© 

© © © 




200 

feet 

OCHHH 
+ + + 

+ + + + + 

rH H H rH rH 

+ + + + + 

+++++ 

rH rH rH rH rH 

+ + + + + 

rHOOOO 

+ 

© © © © © 

© © © 

i 

L. 


Topog¬ 

raphy 

ey-r*A 

auu 

com¬ 

pensa¬ 

tion 

0 

0 

+ 1 
+ 1 
+ 2 

CO if © CO l>- 

© ©rH CM CO 

+ + + + + 

© © t- oo © 

+ + + + + 

© H CM CO **4 

CM CM CM CM CM 

+ + + + + 

©©©r--t''- 
CM CM CM CM CM 

+ + + + + 

© H CM CO TJ4 
CO CO CO CO 

© CO 00 © 

CO CO CO CO CO 

+40 

+41 

+42 

g 



m O 

© © © © © 

© © © © © 

© © © © © 

© rH rH rH rH 

1 1 1 1 

H H H H rH 

1 1 1 1 1 

1 1 1 1 1 

77777 

H H CM CM CM 

1 1 1 1 1 

CM CM CM 

-*-> 

8 

E 

o 

o 


o 

O 

go 

9 +3 
ft 











Topog¬ 

raphy 

+ 0.1 
+ 0.4 
+ 0.8 
+ 1.5 
+ 2.3 

CM CM CO if CO 
CO 4 to© P^ 

+ + + + + 

+ 8.9 
+ 10.1 
+ 11.4 
+ 12.6 
+ 13.9 

rH CO if © © 

© co oo © 

+++++ 

© © © © Tf4 

© H CM CO if 
CM CM CM CM CM 

+ + + + + 

+25.3 

+26.1 

+26.9 

+27.7 

+28.4 

H © ©CO T*4 
© H CO + © 

CO CO CO CO CO 

© 1*4 CO © CM 

© P'» GO © H 
CO CO CO CO 1*4 

+++++ 

+42.4 
+ 43.4 
+44.3 

Mean ele¬ 
vation of 
compart¬ 
ment, 
in feet 

200 

400 

600 

800 

1 000 

1 200 

1 400 

1 600 

1 800 

2 000 

2 200 

2 400 

2 600 

2 800 

3 000 

3 200 

3 400 

3 600 

3 800 

4 000 

4 200 

4 400 

4 600 

4 800 

5 000 

5 200 

5 400 

5 600 

5 800 

6 000 

6 500 

7 000 

7 500 

8 000 

8 500 

9 000 

9 500 
10 000 
11 000 
12 000 

13 000 

14 000 

15 000 






























































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


17 


o 

N 




























































[Inner radius, 1680 meters; outer radius, 2290 meters. Ten compartments.] 


18 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 




3200 

feet 




Tf to CO CO 0- 

r—4 rH i—< i—4 rH 

1 1 1 1 1 

00 00 00 05 

1—4 i-H i-H r-H r-4 

1 1 1 1 1 

05 05 C5 O O 
rH 1-4 T—4 05 05 

1 1 1 1 1 

ooooo 

05 05 1—4 r-4 rH 

1 1 1 1 1 

x x oo 0 - 0 - 

77777 

CO to Tf CO CO 

1 -H rH f—4 rH 1-H 

1 1 1 1 1 



3000 

feet 



CO 

H 

1 

co Tf 40 to CO 

r—4 i—4 rH r—4 1—4 

1 1 1 1 1 

cot^r^t>r>- 

1—4 i—4 r—4 r—4 i-H 

1 1 1 1 1 

CO 00 00 00 00 

r—4 i-H i-H i-H i-H 

1 1 1 1 1 

00 00 00 00 0- 

77777 

0 . i'- co co <o 

1 —4 rH rH rH i—4 

1 1 1 1 1 

Tf Tf CO 05 1-H 

77777 



2800 

feet 



r-4 05 

1—4 r—4 

1 1 

CO CO Tf Tf to 
r—1 r—4 i—4 r—4 i—4 

1 1 1 1 1 

to to co CO CO 

1—4 t— 4 1—4 r-4 r—l 

1 1 1 1 1 

©ONNN 
i-H i-H r—4 i-H 1—4 

1 1 1 I 1 

0 - co co co 

r-4 r—4 rH rH rH 

1 1 1 1 1 

to tO to Tf Tf 

77777 

CO 05 05 rH o 

rH rH rH r—4 i-H 

1 1 1 1 1 



2600 

feet 



-10 

-11 

-11 

05 05 CO CO Tf 

77777 

Tf Tf Tf 40 tO 

1—4 t— 4 i—l r—4 i—4 

1 1 1 1 1 

to to to to »o 

r—4 t— 4 i—4 1—4 i-H 

1 1 1 1 1 

to to to to Tf 

i-H rH r-H 1—4 1-H 

1 1 1 1 1 

Tf Tf co co CO 

rH 1 -H 1—4 1—4 1—4 

1 1 1 1 1 

05 rH O O O 
rH i—4 H rH 

1 1 1 1 1 



2400 

feet 



00)00 
r—( 1—4 

1 M 1 

1-4 1-H 05 05 05 

1—4 i—4 1—4 1—4 r—4 

1 1 1 1 1 

CO CO CO CO Tf 

i-H i-H i-H i-H i-H 

1 1 1 1 1 

Tf Tf Tf Tf Tf 
r-4 1 -H 1—4 1—4 rH 

1 1 1 1 1 

Tf Tf CO CO CO 

rH 1—4 rH T—4 rH 

1 il 1 1 

CO 01 05 05 rH 

77777 

1-HOOC5X 

77 i i i 



2200 

feet 



r- oo oo o o 

1 1 1 1 1 

o O 1-4 1-4 1-4 

77777 

05 05 <05 05 <05 

77777 

05 05 05 05 05 

77777 

05 05 05 05i-4 

r—4 i—4 rH i—4 rH 

1 1 1 1 1 

rH rH i—4 © 

77777 

00*0000?- 

1 1 1 1 1 


4J 

fl 

© 

£ 

J-H 

c3 

ft 

2000 

feet 


CO 

1 

o-r>.oo oo o 

II 1 II 

05 05000 

i—4 i—4 i—4 

1 1 1 1 1 

^0 1—4 i-H t—4 i-H 

77777 

-a 

-ii 

-a 

-ii 

-ii 

rH i—4 1—4 O O 
i-H i—4 rH i-H r—4 

1 1 1 1 1 

O O 05 05 05 

77 i i i 

00XNNCO 

1 1 1 1 1 


1800 

feet 


toco 

1 1 

CONNNCC 

1 1 1 1 1 

00 00 05 05 05 

II 1 1 1 

05 05000 

i 1777 

ooooo 

rH r—l rH rH rH 

1 1 1 1 1 

00 0 0)0) 

7 i i i i 

05 X X X X 

1 1 1 1 1 

r-o- co cO to 

1 1 1 II 


6 

O 

© 

£ 

*© 

W 

1600 

feet 


Tf tO tO 

1 1 1 

O o O CO N 

Mill 

r- oo oo oo 

1 1 1 1 1 

oooooooooo 

1 1 1 1 1 

oooooooooo 

1 1 1 1 1 

00X 00 00 00 

1 1 1 1 1 

1 1 1 1 1 

CO co to to to 

1 1 1 1 1 


1400 

feet 


CO Tf Tf Tf 

1 1 1 1 

tO to to o CO 

1 1 1 1 1 

©ONNN 

1 1 1 1 1 

0-01I> 

II 1 1 1 

r>- 0 - 0 - l- 0 - 

i i i i t 

0 - 0 - 0 - 0 - © 

i i i i i 

CO CO CO co »o 

1 1 1 1 1 

to to Tf Tf Tf 

1 1 1 1 1 



1200 

feet 


05 CO CO CO Tf 

1 1 I 1 1 

-if Tf to to to 

1 1 1 1 1 

to »o CO CO CO 

1 1 1 1 1 

cO cO CO CO CO 

1 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO CO CO to to 

1 1 1 1 1 

tO to to to Tf 

1 1 1 1 1 

Tf Tf Tf eo co 

i i i i i 



1000 

feet 

<M 

1 

05 05 CO CO CO 

Mill 

CO Tf Tf Tf rf 

1 1 1 1 1 

Tf Tf Tf tO t© 

1 1 1 1 1 

to to to to to 

1 1 1 1 1 

tO 40 »o »o to 

1 1 1 1 1 

to to Tf Tf Tf 

1 1 1 1 1 

Tf Tf Tf Tf Tf 

1 1 1 1 1 

CO CO CO CO 05 

1 1 1 1 1 



800 

feet 

rH rH 

1 1 

1 1 1 1 1 

CO CO CO CO CO 

I 1 1 1 1 

CO CO Tf Tf Tf 

1 1 1 1 1 

Tf Tf Tf Tf If 

II 1 1 1 

Tf Tf Tf Tf Tf 

1 1 1 1 1 

Tf Tf co CO CO 

1 1 1 1 1 

CO CO CO CO CO 

II 1 1 1 

05 05 05 05 05 

1 1 1 1 1 

fl 

# o 


600 

feet 

777 

1 1 1 1 1 

05 05 05 05 05 

1 1 1 1 1 

05 CO CO CO CO 

1 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO CO CO CO CO 

1 1 1 1 1 

CO CO 05 05 05 

1 1 1 1 1 

05 05 05 05 05 

1 1 1 1 1 

05 05HHH 

1 1 1 1 1 

CO 

Cm 

O 


400 

feet 

OOi-Ht-H 

1 1 

i—4 1—4 1—4 i—4 rH 

1 1 1 1 1 

r-4 1—4 i-4 1-4 05 

1 1 1 1 1 

05 05 05 05 05 

II 1 1 1 

C5 (05 05 <05 <05 

1 1 1 1 1 

05 05 05 05 05 

1 1 1 1 1 

05 05 05 i-4 r-4 

1 1 II 1 

HHHHH 

1 1 1 1 1 

1—4 rH rH rH rH 

I 1 1 1 1 

a 

t O 

•*-> 

03 


200 

feet 

ooooo 

O OO *—< i—' 

1 1 

r-4 r-4 i—4 1—4 1—4 

1 1 1 1 1 

77777 

t— 4 i—4 i—4 1—4 i-H 

1 1 1 1 1 

i-4 r-4 rH i—4 r—4 

1 1 1 1 1 

1—4 rH rH 1—4 r—4 

1 1 1 1 1 

77777 

rH OOOO 

1 

> 

© 

"© 

u 


3200 

feet 

rH -4 05 CO CO 

Tf t+ t+ to JO 

10 40 0 40© 
+++++ 

CO co to to to 

to to ‘O to to 
+++++ 

Tf Tf Tf Tf Tf 

CO CO CO 05 05 
+ ++ + + 

rH rH rH O O 

+ + + 

rH rH 05 05 CO 

1 1 1 1 1 

£ 

a 

o 


3000 

feet 

HHIN CO CO 

if Tf Tf t-0 »0 
+ + + + + 

40 to to to CO 
++ +++ 

CO CO CO to to 

to to to to to 

to Tf rf Tf Tf 

Tf CO CO 05 05 

05 rH HHO 

O rH rH 05 05 

1 1 1 1 

o 

£ 

U 

O 


2800 

foet 

HHNNCO 

+++++ 

CO Tf Tf 40 40 

»o to to to to 
+++++ 

co »o 40 to iO 

to to to to to 
+++++ 

to Tf Tf Tf Tf 
+ + ++ + 

Tf CO CO CO 05 

05 05 rH rH rH 

O O rH rH 05 

1 1 1 

o 


2600 

feet 

rH rH 05 05 CO 
+++++ 

CO Tf -f rf tO 

40 to to to to 

to to to to to 

to to to to to 

to to Tf Tf Tf 

^CO CO CO 0* 

05 05 05 rH rH 

O O rH rH rH 

1 1 1 



2400 

feet 

rH rH 05 05 CO 

CO Tf Tf Tf 40 
+ + + + + 

JO to to 40 to 

to to to to to 
+++++ 

to to to to to 

to to Tf If Tf 

Tf Tf CO CO CO 

05 05 05 05 rH 
+ + + + + 

rH O O rH rH 
+ 1 1 



2200 

feet 

rH i-4 05 05 X 

CO CO Tf ^1 ^ 

to to to to to 

to to to to to 

40 40 40 to »0 
+++++ 

lO Tf Tf Tf Tf 

-f + + + + 

Tf Tf CO CO CO 

05 05 05 05 rH 
+ + + + + 

rH rH © © rH 

+ + 1 


+3 

fl 

© 

a 

2000 

feet 

hhMNN 
+ + + + + 

CO CO Tf Tf Tf 

Tf lO lO to 40 

to to lO 40 to 

to tO to to to 

Tf Tf Tf Tf Tf 

Tf Tf co coco 
+++++ 

CO 05 05 05 05 
+ + + + + 

rH rHOOO 
+ + 


h 

c3 

ft 

1800 

feet 

M — 

CO CO CO Tf Tf 

TJ4 Tf Tf TJ1JO 

to to to to »o 
+++++ 

to to to to ^f 

Tf Tf Tf Tf Tf 

Tf CO co CO CO 

CO 05 05 05 05 

rH rH rH O O 

+ + + 


fl 

O 

© 

© 

1600 

feet 

OHHNN 
+ + + + 

05 CO CO CO if 
+++++ 

rf f rf rf r}4 

If Tfiif If rf 
+++++ 

Tf Tf If Tf Tf 

Tf Tf Tf Tf Tf 

Tf 00 00 CO M 

CO 05 05 05 05 
+ + + + + 

rH rH rH rH © 

+ + + + 


o 

ifl 

< 

1400 

feet 

O h -h <05 05 
+ + + + 

05 CO CO CO CO 

CO Tf Tf Tf Tf 

Tf Tf Tf Tf Tf 

Tf Tf Tf Tf Tf 

Tf Tf Tf Tf Tf 

CO CO CO CO CO 

05 05 05 05 05 
+ + + + + 

rH rH rH rH © 

+ + + + 



1200 

feet 

OhhhN 
. + + + + 


CO CO CO CO CO 

rj4 Tf if if rji 
+++++ 

Tf Tf Tf Tf Tf 
+++++ 

CO COCO COCO 
+ + + + + 

CO CO COCO CO 

05 05 05 05 05 

hhhho 

++++ 



1000 

feet 

QHHHH 
+ + + + 

05 05 05 05 05 
+ + + + + 

CO CO CO CO CO 

CO CO CO CO CO 
+++++ 

CO COCO CO CO 

CO CO CO CO CO 

-f + 4-4- + 

CO COCO 05 05 

05 05 05 05 05 
+ + + + + 

+++++ 



800 

feet 

O 1—4 i—4 i—4 rH 
+ + + + 

rH 

05 05 05 05 CO 

CO ICO CO CO CO 

CO CO CO CO co 
+ + + + + 

CO CO CO CO 05 

05 05 05 05 05 

05 05 05 05 rH 

rH rH rH rH rH 

+ + + + + 



600 

feet 

© O 1—1 1-4 iH 
+ + + 

+ 1 
+ 1 
+ 1 
+ 1 
+2 

CS 05 

05 05 05 05 05 

<05 05 <05 05 <05 
+++++ 

05 05 05 05 05 
+ + + + + 

05 05 05 05 05 
+ + + + + 

05 »~ 4 rH r—4 rH 
+ + + + + 

+ 1 
+ 1 
+ 1 
+ 1 
+ 1 



400 

feet 

O O O 1-4 1-4 
+ + 

rH H H H rH 

r—4 r—4 i-4 t-4 H 
+++++ 

r-4 1—4 1—4 i-4 i—4 

rH rH t—4 1—4 rH 

r-H rH r—4 rH r—4 

rH rH i—4 i—4 rH 

+ 1 
+ 1 
+ 1 
+ 1 
+ 1 

rH rH rH rH © 

+ + + + 



200 

feet 

OOOOO 

O O O rH i—4 
+ + 

+1 

+1 

+1 

+1 

+1 

+ 1 
+ 1 
+ 1 
+ 1 
+ 1 

+1 

+1 

+1 

+ 1 

+1 

1—4 i—4 rH r—4 r—4 

rH i—4 rH rH rH 

rH rH rH rH CD 

OOOOO 

1 

U 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

OOOOrH 

+ 

r-4 rH 05 05 CO 

+ + + + + 

co Tf rf to co 

+++++ 

NN00 05 0 

+ + + + + 

O i-^ 05 CO CO 

77777 

Tf to co CO 

05 O H CO Tf 
rH 05 05 05 05 

+++++ 

+25 
+26 
+27 
+ 28 
+29 

05 Tf to 0- X 

CO CO CO CO CO 

+++++ 

H-t 

fl 


a a 

ooooo 

OOOOO 

OOOOrf 

1—4 1—4 1—4 1—4 1—4 

T—4 i—4 1—4 r—4 rH 

rH rH rH rH rH 


05 05 05 05 05 

05 05 05 CO CO 

43 

o 

© 

o n.2 





1 1 1 1 1 

1 1 1 1 1 

1 1 1 1 1 

1 II 1 1 

1 II 1 I 

o 

O 

Topog¬ 

raphy 

O rH CO lO X 

ooooo 

++++ 

05 O O lO r-4 

»—4 —4 05 05 CO 

+ + + + + 

NMO©r»4 

CO Tf 40 to CO 

r-4 05 CO Tf (05 

t>» 00 05 © 

+ + + + + 

+ 11.0 
+ 11.8 
+ 12.7 
+ 13.5 
+ 14.3 

+ 15.1 
+ 15.9 
+ 16.7 
+ 17.4 
+ 18.2 

+ 19.7 
+21.2 
+22.6 
+ 24.0 
+25.3 

COXOOh 

CO 0- X © H 
C5 C5 05 CO CO 

CO X X to rH 

CO to 0- ci r-4 

CO CO CO CO Tf 

+++++ 

Mean ele¬ 
vation of 
compart¬ 
ment, 
in feet 

ooooo 

ooooo 

05 rr C© 00 o 

rH 

OOOOO 
ooooo 
05 Tf © X O 

1—4 i-4 r-4 r-4 05 

2 200 

2 400 

2 600 

2 800 

3 000 

3 200 

3 400 

3 600 

3 800 

4 000 

4 200 

4 400 

4 600 

4 800 

5 000 

OOOOO 
OOOOO 
05 Tf © GO O 

to to to to CO 

6 400 

6 800 

7 200 

7 600 

8 000 

OOOOO 
ooooo 
Tf X 05 co o 

X X 05 05 O 

11 000 
12 000 

13 000 

14 000 

15 000 











































































Chapter II.—CORRECTIONS FOR TOPOGRAPHY AND ISOSTATIC COMPENSATION AND 

PRINCIPAL FACTS FOR GRAVITY STATIONS. 

MEAN ELEVATIONS AND CORRECTIONS FOR TOPOGRAPHY AND ISOSTATIC COMPENSATION FOR 

SEPARATE ZONES AT STATIONS IN THE UNITED STATES. 

There are given in the following tables (pp. 20 to 45) the combined effect of the topography 
and compensation for all zones and the separate effects of the topography and the compensa¬ 
tion for each of the lettered zones for the 219 stations in the United States. In addition, there 
is given the mean elevation of the topography for each of the lettered zones for all of the sta¬ 
tions from No. 57 to No. 219. No record of the elevation of the topography for the separate 
zones was made for the first 56 stations, when the topography and compensation effects were 
computed, and it was not deemed expedient to read the maps again to obtain that information 
for publication here. With the combined effect of topography and compensation given for 
separate zones at the first 56 stations one may get from the tables an approximate value of the 
elevation of the topography for the zones. The values of the effects of topography and com¬ 
pensation, separately and combined, are expressed in the fourth decimal place in dynes. Values 
resulting from interpolation from surrounding stations are indicated by italic type. (For 
explanation of process of interpolation, see pp. 58-65 of Special Publication No. 10.) The 
following table gives the radii of the zones and the number of compartments in each of them: 


Designation 
of zone 

Inner radius of 
zone 

Outer radius of 
zone 

Compartments 


Meters 


Meters 



A 


0 



2 


1 

B 


2 



68 


4 

C 


68 



230 


4 

D 


230 



590 


6 

E 


590 


1 

280 


8 

F 

1 

280 


2 

290 


10 

G 

2 

290 


3 

520 


12 

H 

3 

520 


5 

240 


16 

I 

5 

240 


8 

440 


20 

J 

8 

440 


12 

400 


16 

K 

12 

400 


18 

800 


20 

L 

18 

800 


28 

800 


24 

M 

28 

800 


58 

800 


14 

N 

58 

800 


99 

000 


16 

0 

99 

000 


166 

700 


28 


O 

/ 

// 

O 

/ 

// 


18 

1 

29 

58 

1 

41 

13 

1 

17 

1 

41 

13 

1 

54 

52 

1 

16 

1 

54 

52 

2 

11 

53 

1 

15 

2 

11 

53 

2 

33 

46 

1 

14 

2 

33 

46 

3 

03 

05 

1 

13 

3 

03 

05 

4 

19 

13 

16 

12 

4 

19 

13 

5 

46 

34 

10 

11 

5 

46 

34 

7 

51 

30 

8 

10 

7 

51 

30 

10 

44 


6 

9 

10 

44 


14 

09 


4 

8 

14 

09 


20 

41 


4 

7 

20 

41 


26 

41 


2 

6 

26 

41 


35 

58 


18 

5 

35 

58 


51 

04 


16 

4 

51 

04 


72 

13 


12 

3 

72 

13 


105 

48 


10 

2 

105 

48 


150 

56 


6 

1 

150 

56 


180 



1 


19 













20 


IT. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Corrections for topography and isostatic compensation, separate zones, for United States stations. 


Zone 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Cora- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Key West, Fla., 

West Palm Beach, 

Punta Gorda, Fla., 

9 

Apalachicola, Fla., 

New Orleans, La., 

Rayville, 

La., 



No. 1 


Fla., No 

2 


No. 3 



No. 4 



No. 5 



No. 6 


A 

+1 

0 

+ 1 

+2 

0 

+ 2 

+1 

0 

+ 1 

+2 

0 

+ 2 

+ 1 

0 

+ 1 

4" 2 

0 

4- 2 

B 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 20 

0 

+20 

C 

-1 

0 

- 1 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 4 

0 

+ 4 

D 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 6 

0 

+ 6 

E 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

F 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

G 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

H 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

J 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

K 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

L 

0 

0 

0 

0 

+ 5 

+ 5 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

M 

0 

+ 14 

+ 14 

0 

+20 

+ 20 

• 0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

N 

0 

+42 

+ 42 

0 

+24 

+ 24 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+55 

+ 55 

0 

+16 

+ 16 

0 

0 

0 

0 

+6 

+ 6 

0 

0 

0 

0 

0 

0 

18 



+ 8 



-f- 4 



0 



+ 2 



+ 2 



- 1 

17 



+ 4 



+ 5 



+ 1 



+ 3 



+ 2 



— 1 

16 



+ 3 



+ 5 



+ 2 



4- 4 



+ 5 



— 1 

15 



+ 5 



+ 5 



+ 6 



+ 9 



+ 7 



— 2 

14 



+ 8 



+ 9 



+ 10 



+ ii 



+ 11 



— 3 

13 



+ 38 



+ S3 



+ so 



+ 17 



+ 24 



+ 5 

12 



+ 38 



+ 39 



+ 31 



+ 11 



+ 22 



+ 5 

11 



+ 42 



+ 45 



+ S3 



+ 9 



+ 7 



0 

10 



+ 25 



+ 27 



+ 22 



+ 14 



+ 3 



— 1 

9 



+ 15 



+ 15 



+ 14 



+ 12 



- 2 



— 3 

8 



+ 15 



+ 15 



+ 13 



+ 10 



+ 5 



+ 3 

7 



+ 5 



+ 5 



+ 5 



+ 6 



+ 7 



+ 8 

0 



+ 6 



+ 5 



+ 6 



+ 8 



+ 10 



+ 9 

5 



+ 10 



+ 10 



+ 10 



+ 10 



+ 10 



+11 

4 



+ 8 



H- 8 



+ 8 



+ 7 



+ 8 



4- 7 

3 



4- 6 



+ 6 



+ 6 



+ 6 



+ 6 



4- 5 

2 



+ 2 



+ # 



4- 2 



4- 3 



4- 3 



4- 3 

1 



+ 1 



+ 1 



+ i 



+ 1 



+ 1 



+1 








. 






Total. 



+350 



+306 



+201 



+151 



+ 132 



+77 















Galveston, Tex., 

Point Isabel 

Tex., 

Laredo, Tex., 

Austin, 

Tex. (Capitol), 

Austin 

, Tex 

(Uni- 

McAlester, Okla.. 



No. 7 



No. 8 



No. 9 


No. 10 


versity), No. 11 

No. 12 


A 

+2 

0 

+ 2 

+2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

4- 2 

0 

4- 2 

+ 2 

0 

+ 2 

B 

0 

0 

0 

+4 

0 

+ 4 

+ 56 

0 

+56 

+56 

0 

+56 

+56 

0 

+56 

+60 

0 

+60 

C 

0 

0 

0 

0 

0 

0 

+ 50 

0 

+50 

+64 

0 

+ 64 

4*72 

0 

+ 72 

+87 

0 

+ 87 

D 

0 

0 

0 

0 

0 

0 

+ 21 

0 

+ 21 

+34 

0 

+34 

+40 

0 

+40 

+52 

0 

+52 

E 

0 

0 

0 

0 

0 

0 

+ 8 

0 

+ 8 

+ 15 

0 

+ 15 

+ 16 

0 

+ 16 

+21 

0 

+21 

F 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 2 

0 

+ 2 

+ 6 

0 

+ 6 

+ 10 

0 

+ 10 

G 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

H 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

J 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

-14 

-14 

0 

-14 

-14 

0 

-13 

-13 

K 

0 

0 

0 

0 

0 

0 

0 

- 4 

- 4 

0 

-18 

-18 

0 

-18 

-18 

0 

-16 

-16 

L 

0 

0 

0 

0 

0 

0 

0 

-10 

-10 

0 

-22 

-22 

0 

-22 

-22 

0 

-22 

-22 

M 

0 

0 

0 

0 

0 

0 

0 

-24 

-24 

0 

-41 

-41 

0 

-41 

-41 

0 

-46 

-46 

N 

0 

0 

0 

0 

- 1 

- 1 

0 

-26 

-26 

0 

-43 

-43 

0 

-43 

-43 

0 

-35 

-35 

0 

0 

0 

0 

0 

+ 27 

+ 27 

0 

-21 

-21 

0 

-44 

-44 

0 

-44 

-44 

0 

-40 

-40 

18 



0 



+ 10 



- 5 



— 8 



8 



8 

17 



+ 2 



+ 12 



- 6 



— 8 



— 8 



Q 

16 



+ 3 



+ 13 



- 7 



— 7 



7 



9 

15 



+ 4 



+ 15 



-10 



— 7 



— 7 



q 

14 



+ 6 



+ 14 



- 8 



— 7 



7 



q 

13 



+ 6 



+ 12 



-21 



-12 



—12 



15 

12 



+ 4 



- 1 



-10 



- 9 



— 9 



13 

11 



- 2 



- 9 



-12 



— 7 



— 7 



12 

10 



- 6 



- 5 



- 4 



-11 



ii 



IS 

9 



+ 1 



+ 5 



+ 4 



+ 1 



4- / 



/ 

8 



+ 7 



+ 9 



+ 10 



•f 7 



4- 7 



4 

7 



+ 8 



+ 9 



+ 9 



+ 9 



4- Q 



T * 

6 



+ 10 



+ 10 



+10 



4-70 



_i_ m 




5 



+ 10 



+ 10 



+10 



4 -to 



4- in 



i_11 

4 



+ 9 



+ 9 



+ 9 



4- 9 



4- Q 




3 



+ 6 



+ 6 



+ 6 



4- 6 



4- 



T o 

2 



+ 2 



+ 2 



4- 2 



4- 2 






*r o 

1 



+ 1 



+ 1 



+ 1 



+ / 



+ 1 



~r o 

















4* i 

Total. 



+74 



+ 154 



+30 



-30 



-11 



+ 8 


1 






















































































































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


21 


Corrections for topography and isostatic compensation, separate zones, for United States stations —Continued. 


Zone 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Cora- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Little 

Rock, Ark., 
No. 13 

Columbia, Tenn., 
No. 14 

Atlanta, Ga., 

No. 15 

McCormick, 
No. 16 

S. C., 

Charleston, S. C., 
No. 17 

Beaufort, N. 

18 

G, No. 

A 

4* 2 

0 

+ 2 

+ 2 

0 


+ 2 

0 

+ 2 

4- 2 

0 

4- 2 

+2 

0 

+ 2 

+1 

0 

+ 1 

B 

+48 

0 

+48 

+60 

0 

+60 

+ 64 

0 

+ 64 

+56 

0 

+ 56 

+4 

0 

+ 4 

0 

0 

0 

C 

+31 

0 

+31 

+78 

0 

+78 

+104 

0 

+ 104 

+64 

0 

+ 64 

0 

0 

0 

0 

0 

0 

D 

+ 12 

0 

+12 

+48 

0 

+48 

+ 90 

0 

+ 90 

+30 

0 

+ 30 

0 

0 

0 

0 

0 

0 

E 

+ 5 

0 

+ 5 

+19 

0 

+19 

+ 40 

0 

+ 40 

+ 13 

0 

+ 13 

0 

0 

0 

0 

0 

0 

F 

0 

0 

0 

+ 7 

0 

+ 7 

+ 19 

0 

+ 19 

0 

0 

0 

0 

0 

0 

0 

0 

0 

G 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

H 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

J 

0 

0 

0 

0 

-12 

-12 

0 

-16 

- 16 

0 

- 2 

- 2 

0 

0 

0 

0 

0 

0 

K 

0 

- 1 

- 1 

0 

-16 

-16 

0 

-20 

- 20 

0 

- 5 

- 5 

0 

0 

0 

0 

0 

0 

L 

0 

0 

0 

0 

-17 

-17 

0 

-24 

- 24 

0 

- 7 

- 7 

0 

0 

0 

0 

0 

0 

M 

0 

-20 

-20 

0 

-34 

-34 

0 

-50 

- 50 

0 

-28 

- 28 

0 

0 

0 

0 

0 

0 

N 

0 

-30 

-30 

0 

-39 

-39 

0 

-44 

- 44 

0 

-31 

- 31 

0 

-1 

- 1 

0 

+ 4 

+ 4 

0 

0 

-29 

-29 

0 

-42 

-42 

0 

-49 

- 49 

0 

-37 

- 37 

0 

+2 

+ 2 

0 

+45 

+ 45 

18 



— 5 



— 7 



- 9 



- 7 



+ 2 



+ 14 

17 



— 5 



— 7 



- 10 



- 8 



+ 2 



+ 16 

16 



— 5 



— 6 



- 9 



- 8 



+ 2 



+ 20 

15 



— 5 



— 6 



- 7 



- 3 



+ 3 



+ 27 

14 



— 5 



— 7 



- 6 



- 3 



+ 4 



+ 34 

13 



3 



—10 



- 7 



- 1 



+ 12 



+ 52 

12 



_ 7 



— 5 



— 1 



+ 7 



+ 21 



+ 36 

ll 



_ 5 



0 



+ 6 



+ IS 



+ 24 



+ 29 

10 



— 2 



4- 6 



+ 14 



+ 17 



+ 21 



+ 19 

9 



— 5 



4- 3 



+ 9 



+ 10 



+ 13 



+ 14 

3 



4- 2 



4- h 



+ 6 



+ 8 



+ 13 



+ 14 

7 



4- 8 



4- 6 



+ 6 



+ 6 



+ 5 



+ 5 

5 



4- 9 



4- 7 



+ 7 



+ 7 



+ 6 



+ 6 




4 -11 



4 -10 



+ 10 



+ 10 



+ 9 



+ 8 

4 



4- 7 



4- 7 



+ 7 



+ 7 



+ 7 



+ 7 

q 



4- a 



4 - o 



+ 6 



+ 6 



+ 6 



+ 6 

2 



4- 8 



4- 3 



4- 3 



+ 3 



+ 8 



+ 3 

1 



+1 



+1 



+ 1 



+ 1 



+ 1 



+ 1 




4-19 



+59 



+142 



+ 120 



+159 



+301 



















Charlottesville, Va., 
No. 19 


Deer Park, Md., No. 20 


Washington, D. C., 
C. and G. S. Office, 
No. 21 


Washington, D. C., 
Smithsonian Insti¬ 
tution, No. 22 


Baltimore, Md., No. 23 


Philadelphia, Pa., 
No. 24 


A 

B 

C 

D 

E 

F 

G 

H 

1 
J 

K 

L 

M 

N 

O 

18 

17 

16 

15 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

Total. 


+ 2 
+56 
+62 
+33 

+11 

+ 3 
0 
0 
0 
0 

0 

0 

0 

0 

0 


0 

0 

0 

0 

0 

0 

0 

0 

0 

- 7 

-11 

-21 

-52 

-46 

-52 


+ 2 
+56 
+62 
+33 
+11 

+ 3 
0 
0 
0 

- 7 

-11 

-21 

-52 

-46 

-52 

-10 

- 9 

- 8 

- 7 

- 7 

-10 
+ 8 
+13 
+ 18 
+ 12 

+11 
+ 5 
+ 6 
+ 8 
+ 7 


+ 6 
+ 3 
+ 1 


+25 


+ 2 
+ 68 
+144 
+209 
+186 

+ 101 
+ 52 
+ 36 
+ 20 
+ 16 

0 

0 

0 

0 

0 


0 

0 

0 

0 

- 8 

-10 

-12 

-16 

-20 

-32 

-36 

-59 

-97 

-79 

-72 


+ 2 
+ 68 
+ 144 
+ 209 
+ 178 


91 

40 


+ 20 
0 

- 16 

- 36 

- 59 

- 97 

- 79 

- 72 

- 11 
- 10 
- 10 
- 8 
- 8 

- 11 
+ * 
+ 7 
+ 13 

+ 10 
+ 10 

+ 5 
+ 6 
+ 8 
+ 7 

+ 6 
+ S 
+ 1 


+413 


+ 2 

0 

4- 2 

+2 

0 

+ 2 

+ 2 

0 

+12 

0 

+12 

+8 

0 

+ 8 

+24 

0 

+ 2 

0 

+ 2 

0 

0 

0 

+ 4 

0 

0 

0 

0 

0 

0 

0 

+ 6 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

- 1 

0 

0 

0 

0 

0 

0 

0 

- 2 

0 

0 

0 

0 

0 

0 

0 

- 3 

0 

-12 

-12 

0 

-12 

-13 

0 

-20 

0 

-17 

-17 

0 

-17 

-17 

0 

-16 

0 

-23 

-23 

0 

-23 

-33 

0 

-20 



— 5 



- 5 





— 8 



- 8 





- 9 



- 9 





- 8 



- 8 





— 4 



- 4 





4- 3 



+ 3 





+13 



+ 13 





+18 



+18 





+ 17 



+ 17 





+ 11 



+ 11 





+13 



+13 





4- 6 



+ 6 





4- 6 



+ 6 





+ 7 

. 

...... 

+ 7 

. 

. 



+ 6 



+ 6 





4- 6 



+ 6 





+ 4 



+ 4 





+1 



+ 1 





+40 



+34 











+ 2 
+24 
+ 4 
+ 6 
0 

0 

0 

0 

0 

- 1 

- 2 

- 3 
-20 
-16 
-20 

- 6 

- 7 

- 9 

- 8 
- 3 

+ 7 
+ 14 
+19 
+17 
+10 

+ 13 

+ e 
+ 6 
+ 7 
+ 6 

+ 6 
+ 4 
+ 1 


+57 


4- 2 

+12 
+ 4 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

- 6 
-10 
-19 

























. 

. 














+ 2 
+12 
+ 4 
0 
0 

0 

0 

0 

0 

0 

0 

0 

- 6 
-10 
-19 

- 3 

- 6 
- 6 

- 3 
0 

+ 13 
+19 
+31 
+ 10 
+ 11 

+14 
+ 6 
+ 6 
+ 6 
+ 6 

+ 6 
+ 4 
+ 1 


+93 












































































































































































































































































































22 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


Corrections for topography and isostatic compensation, separate zones, for United States stations —Continued. 





Topog- 



Topoe- 



Topog- 



Topog- 


Com- 

Topog- 


Com- 

Topog- 



Com- 

raphy 


Com- 

raphy 


Com- 

raphy 


Com- 

raphy 


raphy 

Topog- 

raphy 


Topog- 

pen- 

and 

Topog- 

pen- 

and 

Topog- 

pen- 

and 

Topog- 

pen* 

and 

Topog- 

pen- 

and 

pen- 

and 


raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

Zone 

tion 

pensa- 

tion 

pensa- 

tion 

pensa- 

tion 

pensa- 


tion 

pensa- 


tion 

pensa- 



tion 



tion 



tion 



tion 



tion 



tion 


Princeton, 

N. J., 

Hoboken, N. J., 

New York, N. Y., 

Worcester, Mass., 

Boston, Mass., 

Cambridge, Mass., 



No. 25 


No. 26 


No. 27 


No. 28 


No. 29 


No. 30 

A 

4- 2 

0 

+ 2 

+2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

4- 2 

0 

+ 2 

B 

+ 40 

0 

+ 40 

+8 

0 

+ 8 

+27 

0 

+ 27 

+56 

0 

+ 56 

+ 16 

0 

+ 16 

+ 12 

0 

+ 12 

C 

+ 16 

0 

+ 16 

0 

0 

0 

+ 7 

0 

+ 7 

+64 

0 

+ 64 

+ 4 

0 

+ 4 

0 

0 

0 

D 

+ 6 

0 

+ 6 

0 

0 

0 

+ 2 

0 

+ 2 

+31 

0 

+ 31 

+ 1 

0 

+ 1 

0 

0 

0 

E 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+11 

0 

+ 11 

0 

0 

0 

0 

0 

0 

F 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 7 

0 

+ 7 

0 

0 

0 

0 

0 

0 

G 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

n 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

i 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

j 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

-10 

- 10 

0 

0 

0 

0 

- 2 

- 2 

K 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

-13 

- 13 

0 

0 

0 

0 

- 3 

- 3 

L 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

-14 

- 14 

0 

0 

0 

0 

- 3 

- 3 

M 

0 

-11 

- 11 

0 

-12 

-12 

0 

-12 

- 12 

0 

-27 

- 27 

0 

- 4 

- 4 

0 

- 9 

- 9 

N 

0 

-16 

- 16 

0 

-18 

-18 

0 

-18 

- 18 

0 

-25 

- 25 

0 

-12 

- 12 

0 

-15 

- 15 

0 

0 

-22 

- 22 

0 

-25 

-25 

0 

-26 

- 26 

0 

-28 

- 28 

0 

-10 

- 10 

0 

-14 

- 14 

18 



— 4 



— 6 



— 6 



- 2 



- 2 



— 2 

17 

16 



— 6 



— 5 



— 5 



— 3 



— l 



~ 1 

— 2 



— 5 



— 3 



— 3 



— 4 



— 1 



15 



— 1 



+ 1 



+ i 
+ 3 

+ 14 
+ 22 
+ 21 
+ 16 
+ 11 

+ 15 
+ 6 
+ 6 



— 2 



— 2 



— 2 

14 



+ 1 

+ 13 



+ 3 

+14 

+22 

+21 

+16 

+11 

+ 15 
+ 6 
+ 6 
+ 6 
+ 6 

+ 6 
+ 4 
+ 1 





- 2 



— 2 



- 2 

+ 10 
+ 25 
+ 25 
+ 18 
+ 12 

+ 17 
+ 6 
+ 6 
+ 6 
+ 6 

+ 6 
+ 4 

-P i 

13 

12 









+ 9 
+ 24 
+ 23 
+ 17 



+ ii 

+ 26 





+ 20 
+ 21 
+ 16 
+ 11 











11 











+ 25 
+ 18 

+ 12 



10 













9 









+ 12 

+ 17 





8 



+ 14 
+ 6 
+ 6 
+ 6 
+ 6 

+ 6 
+ 4 
+ 1 









+ 17 
+ 6 
+ 6 
+ 6 
+ 6 

+ 6 
+ 4 



7 









+ 6 





6 

5 









+ 6 
+ 6 
+ 6 











+ 6 
+ 6 

+ 6 
+ 4 
+ 1 







4 













3 









+ 6 
+ 4 

+ i 





2 













i 











+ 1 


















Total 



+130 



+79 



+ 106 



+ 178 



+ 133 



+ 101 















Calais, Me., 

No. 31 

Ithaca, N. Y. 

,No. 32 

Cleveland, Ohio, 
No. 33 

Cincinnati, 
No. 34 

Ohio, 

Terre Haute 
No. 35 

, Ind., 

Chicago, HI., No. 36 

A 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

4- 2 

0 

4~ 2 

B 

+ 25 

0 

+ 25 

+60 

0 

+60 

+58 

0 

+58 

+60 

0 

+60 

+56 

0 

+56 

+56 

0 

+56 

C 

+ 4 

0 

+ 4 

+88 

0 

+88 

+78 

0 

+78 

+84 

0 

+84 

+60 

0 

+60 

+72 

0 

+72 

D 

+ 4 

0 

+ 4 

+59 

0 

+59 

+48 

0 

+ 48 

+57 

0 

+57 

+28 

0 

+ 28 

+42 

0 

+42 

E 

0 

0 

0 

+27 

0 

+27 

+20 

0 

+20 

+22 

0 

+22 

+ 12 

0 

+ 12 

+ 16 

0 

+ 16 

F 

0 

0 

0 

+ 6 

0 

+ 6 

+10 

0 

+10 

0 

0 

0 

4- 2 

0 

+ 2 

+ 4 

0 

+ 4 

G 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

H 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

I 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

0 

J 

0 

0 

0 

0 

-16 

-16 

0 

-16 

-16 

0 

-11 

-11 

0 

- 8 

- 8 

0 

- 7 

- 7 

K 

0 

0 

0 

0 

-20 

-20 

0 

-20 

-20 

0 

-17 

-17 

0 

-10 

-10 

0 

- 9 

- 9 

L 

0 

0 

0 

0 

-32 

-32 

0 

-24 

-24 

0 

-20 

-20 

0 

-12 

-12 

0 

-11 

-11 

M 

0 

- 5 

- 5 

0 

-50 

-50 

0 

-42 

-42 

0 

-42 

-42 

0 

-30 

-30 

0 

-22 

-22 

N 

0 

- 4 

- 4 

0 

-56 

-56 

0 

-41 

-41 

0 

-50 

-50 

0 

-37 

-37 

0 

-26 

-26 

0 

0 

-15 

- 15 

0 

-58 

-58 

0 

-45 

-45 

0 

-48 

-48 

0 

-35 

-35 

0 

-23 

-23 

18 



- 3 



- 8 



— 9 



— 8 



— 6 



6 

17 



— 3 



— 8 



-10 



— 8 



- 6 
- 6 
- 6 
_ 7 



- 6 
7 

16 



— 3 



- 7 



-10 



— 8 





15 



- 4 



— 7 



-11 



— 8 





- 8 
g 

14 



- 3 



— 7 



-11 



- 8 





13 



- 3 



- 6 



— 18 



—15 



-16 

- 9 

— 7 



-16 

-10 

/ 

12 



+ 9 



+ 7 



— 10 



- 8 





11 



+ 18 



+ 8 



- 5 



— 3 





10 



+ 18 



+ 11 
+ 8 



+ 4 
+ 5 

+ 8 
+ 6 
+ 7 



+ 4 
+ 4 

+ 6 
+ 6 
+ 7 
+ 9 
+ 7 

+ 5 



- 2 
+ 1 

+ 4 

+ 7 
+ 8 
+ 9 
+ 7 

+ 5 



- 1 
+ 1 

+ 6 
-4- 7 

9 



+ 13 











8 



+ 16 



+12 









7 



+ 6 



+ 6 
+ 6 









6 



+ 6 











+ 8 
+ 9 
+ 7 

+ 5 
+ 3 
+ 1 

5 



+ 5 



+ 7 
+ 6 

+ 6 



+ 8 
+ 7 







4 



+ 6 











3 



+ 6 





+ 5 







2 



+ 5 



+ 4 
+ 1 



+ 3 

+ 1 



+ 3 
+ 1 



+ 3 
+ 1 



1 



+ 1 
























Total. 



+ 101 



+ 49 



— 2 



+23 



+ 8 



+74 


















































































































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


23 


Corrections for topography and isostatic compensation, separate zones, for United States stations —Continued. 




Com- 

Topog- 



Topog- 



Topog- 



Topog- 



Topog- 



Topog- 



raphv 


Com- 

raphv 


Com- 

raphy 


Com- 

raphv 


Com- 

raphy 


Com- 

raphy 

Zone 

Topog- 

pen- 

and 

Topog- 

pen- 

and 

Topog- 

pen- 

and 

Topog- 

pen- 

and 

Topog- 

pen- 

and 

Topog- 

pen- 

and 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 

raphy 

sa- 

com- 



tion 

pensa- 


tion 

pensa- 


tion 

pensa- 


tion 

pensa- 


tion 

pensa- 


tion 

pensa- 




tion 



tion 



tion 



tion 



tion 



tion 


Madison, Wis., 

St. Louis, Mo., 

Kansas City, Mo., 

Ellsworth, Kans., 

Wallace, Kans., 

Colorado Springs, 



No. 37 

No. 38 

No. 39 

No. 40 

No. 41 


Colo., No. 

42 

A 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

B 

+62 

0 

+62 

+56 

0 

+56 

+64 

0 

+64 

+ 68 

0 

+ 68 

+ 08 

0 

+ 68 

+ 68 

0 

+ 68 

C 

+95 

0 

+95 

+60 

0 

+60 

+97 

0 

+97 

+ 124 

0 

+ 124 

+152 

0 

+ 152 

+164 

- 4 

+ 160 

D 

+70 

0 

+70 

+30 

0 

+30 

+72 

0 

+72 

+ 140 

0 

+140 

+252 

- 6 

+246 

+312 

- 6 

+306 

E 

+30 

0 

+30 

+ 13 

0 

+13 

+30 

0 

+30 

+ 82 

0 

+ 82 

+256 

- 8 

+248 

+424 

- 16 

+408 

F 

+10 

0 

+10 

0 

0 

0 

+16 

0 

+ 16 

+ 40 

0 

+ 40 

+150 

- 10 

+140 

+351 

- 20 

+331 

G 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 12 

0 

+ 12 

+ 84 

- 12 

+ 72 

+216 

- 24 

+ 192 

H 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 16 

-16 

0 

+ 48 

- 16 

+ 32 

+159 

- 32 

+ 127 

I 

0 

0 

0 

0 

0 

0 

0 

0 

0 

+ 20 

-20 

0 

+ 60 

- 40 

+ 20 

+ 138 

- 60 

+ 78 

J 

0 

-16 

-16 

0 

- 3 

- 3 

0 

-16 

-16 

0 

-16 

- 16 

+ 24 

- 40 

- 16 

+ 63 

- 74 

- 11 

K 

0 

-20 

-20 

0 

-12 

-12 

0 

-20 

-20 

0 

-20 

- 20 

+ 10 

- 50 

- 40 

+ 52 

-123 

- 71 

L 

0 

-24 

-24 

0 

-13 

-13 

0 

-24 

-24 

0 

-47 

- 47 

+ 12 

- 84 

- 72 

+ 31 

-178 

-147 

M 

0 

-57 

-57 

0 

-28 

-28 

0 

-53 

-53 

+ 2 

-89 

- 87 

+ 6 

-217 

-211 

+ 30 

-399 

-369 

N 

0 

-48 

-48 

0 

-32 

-32 

0 

-47 

-47 

0 

-85 

- 85 

0 

-192 

-192 

+ 17 

-359 

-342 

0 

0 

-49 

-49 

0 

-33 

-33 

0 

-55 

-55 

0 

-95 

- 95 

0 

-169 

-169 

+ 13 

-352 

-339 

18 



_ 7 



— 5 



-10 



- 19 



- 36 



- 68 

17 

Id 

15 



_ 7 



— 5 



-10 



- 19 



- 36 



- 69 



— 8 



— 5 



—10 



- 19 



- 36 



- 69 



— 8 



— 7 



-11 



- 19 



- 37 



- 68 

14 

13 

12 

11 

10 

9 

8 

7 



— 9 



— 9 



-11 



- 20 



- 39 



- 62 



-16 



-16 



-20 



- 44 



- 69 



- 81 



-10 
— 3 



—10 



-13 



- 26 



- 38 



- 48 





— 9 



-14 



- 19 



- 25 



- 30 



— 2 



— 5 



— 14 



- 15 



- 16 



- 17 



0 



— 2 



- 8 



- 4 



- 2 



0 



+ 6 
+ 7 
+ 8 
+ 9 
+ 7 

+ 5 



+ 2 
+ 7 
+ 8 
+ 10 
+ 7 

+ 5 
+ 3 
+ 1 



- 1 



+ 3 



+ 6 



+ 9 







+ 8 



+ 7 



+ 7 



+ 7 

6 







+ 9 
+ 11 
+ 7 

+ o 
+ 3 
+ 1 



+ 9 



+ 9 



+ 9 

5 









+ 10 



+ 10 



+ 9 

4 









+ 8 



+ 8 



+ 8 

3 

2 









+ 6 



+ 6 



+ 5 



4- s 







+ 3 



+ 3 



+ 3 

i 



+1 







+ 1 



+ 1 



+ 1 




















+31 



+ 10 



-12 



- 40 



- 5 



- 68 






1 











Pikes Peak 

Colo.. 

Denver, Colo., 

Gunnison, Colo., 

Grand Junction, 

Green River, Utah, 

Pleasant Valley June- 



No. 43 

No. 44 

No. 45 

Colo., No 

. 46 

No. 47 

tion, Utah, No. 48 

A 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

B 

+ 80 

- 8 

+ 72 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

C 

+165 

- 8 

+ 157 

+ 164 

- 4 

+160 

+ 168 

- 4 

+164 

+164 

- 4 

+160 

+156 

0 

+156 

+164 

- 4 

+160 

D 

+325 

- 15 

+ 310 

+306 

- 6 

+300 

+330 

- 6 

+324 

+288 

- 6 

+282 

+276 

- 6 

+270 

+324 

— 6 

+318 

E 

+545 

- 25 

+ 520 

+392 

- 8 

+384 

+488 

- 16 

+472 

+344 

- 8 

+336 

+310 

- 8 

+302 

+467 

— 16 

+451 

F 

+639 

- 37 

+ 602 

+310 

- 20 

+290 

+450 

- 20 

+430 

+249 

- 10 

+239 

+209 

- 10 

+199 

+419 

- 20 

+399 

G 

+552 

- 40 

+ 512 

+ 192 

- 24 

+168 

+309 

- 24 

+285 

+ 136 

- 16 

+ 120 

+109 

- 12 

+ 97 

+278 

- 24 

+254 

H 

+498 

- 55 

+ 443 

+ 130 

- 32 

+ 98 

+240 

- 38 

+202 

+ 89 

- 23 

+ 66 

+ 72 

- 16 

+ 56 

+208 

— 34 

+174 

I 

+503 

- 91 

+ 412 

+ 100 

- 40 

+ 60 

+210 

- 80 

+ 130 

+ 75 

- 42 

+ 33 

+ 67 

- 40 

+ 27 

+ 175 

— 74 

+ 101 

J 

+298 

- 97 

+ 201 

+ 48 

- 48 

0 

+ 103 

- 81 

+ 22 

+ 44 

- 51 

- 7 

+ 32 

- 48 

- 16 

+ 84 

— 80 

+ 4 

K 

+221 

-142 

+ 79 

+ 40 

- 80 

- 40 

+ 87 

-143 

- 56 

+ 33 

- 98 

- 65 

+ 22 

- 73 

- 51 

+ 91 

-140 

- 49 

L 

+152 

-184 

- 32 

+ 22 

-120 

- 98 

+ 53 

-221 

-168 

+ 24 

-156 

-132 

+ 14 

-115 

-101 

+ 61 

—203 

—142 

M 

+142 

-432 

- 290 

+ 21 

-383 

-362 

+ 42 

-568 

-526 

+ 10 

-401 

-391 

+ 12 

-341 

-329 

+ 49 

—427 

—378 

N 

+ 50 

-384 

- 334 

+ 13 

-389 

-376 

+ 31 

-493 

-462 

+ 8 

-382 

-374 

+ 16 

-311 

-295 

+ 17 

—360 

—343 

0 

+ 42 

-371 

- 329 

+ 18 

-364 

-346 

+ 17 

-426 

-409 

+ 14 

-363 

-349 

0 

-324 

—324 

+ 4 

—319 

—315 

18 

17 

16 

15 



- 68 
- 68 
- 68 
- 64 



- 68 

- 67 

- 67 

- 64 



- 76 



- 74 



— 65 



- 59 







- 74 



- 73 



- 70 



- 61 







- 68 



- 72 



- 67 



- 63 







- 64 

- 62 

- 97 

- 52 

- 33 



- 66 

- 65 

-101 

- 55 

- 34 



- 68 

- 69 

-108 

- 59 

- 35 



- 64 

- 65 

-104 

- 68 
- 35 

14 

13 



- 59 

- 83 



- 63 

- 84 









12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 



- 1,8 

- 30 

- 17 

0 

+ 9 

+ 7 

+ 9 

+ 9 

+ 8 

+ 5 

+ 3 

+ 1 



+++ +++++ 111 

*—». CO +» 

»■< Cq Cr* OoC;CO^^Ci ONOOC 















- 18 



- 15 



- 12 



- 14 







+ 2 

+ 11 
+ 7 



+ 8 



+ 4 



+ 4 









+ 11 



+ 11 



+ 11 









+ 7 



+ 8 



+ 7 







+ 9 
+ 9 



+ 9 
+ 9 



+ 9 
+ 9 



+ 9 
+ 9 







+ 8 

+ 5 



+ 8 

+ 5 



+ 8 

+ 5 



+ 8 

+ 5 







+ 3 
+ 1 



+ 3 
+ / 



+ 3 
"f* 1 



+ S 
+ 1 



+1871 



-148 



- 11 



-511 



-434 



+238 

i otai. 









1 

1 




















































































































































































































































































































24 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Corrections for topography and isostatic compensation, separate zones, for United States stations —Continued. 


Zone 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Salt Lake City, 

Grand Canyon, 

Norris Geyser Basin, 

Lower Geyser Basin, 

Seattle 

, Wash. (Uni- 

San Francisco, Cal., 


Utah, No. 49 

Wyo., No. 50 

Wyo., No. 51 

Wyo., No. 52 

versity), No. 53 


No. 54 

A 

4- 2 

0 

4- 2 

4- 2 

0 

+ 2 

+ 2 

0 

4- 2 

+ 2 

0 

+ 2 

+ 2 

0 

+ 2 

4- 2 

0 

4- 2 

B 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

+ 68 

0 

+ 68 

+33 

0 

+ 33 

+48 

0 

+ 48 

C 

+160 

- 4 

+ 156 

+168 

- 4 

+ 164 

+168 

- 4 

+ 164 

+164 

- 4 

+ 160 

+12 

0 

+ 12 

+35 

0 

+ 35 

D 

+282 

- 6 

+276 

+333 

- 6 

+327 

+330 

- 6 

+324 

+324 

- 6 

+318 

+ 6 

0 

+ 6 

+ 15 

0 

+ 15 

E 

+333 

- 8 

+325 

+ 489 

- 16 

+473 

+ 480 

- 16 

+ 464 

+475 

- 16 

+459 

+ 1 

0 

+ 1 

+ 1 

0 

+ 1 

F 

+226 

- 10 

+216 

+ 449 

- 20 

+429 

+431 

- 20 

+ 411 

+423 

- 20 

+403 

0 

0 

0 

0 

0 

0 

G 

+125 

- 16 

+ 109 

+312 

- 24 

+288 

+288 

- 24 

+ 264 

+278 

- 24 

+254 

0 

0 

0 

0 

0 

0 

H 

+ 81 

- 22 

+ 59 

+242 

- 43 

+ 199 

+218 

- 34 

+ 184 

+ 208 

- 32 

+ 176 

0 

0 

0 

0 

0 

0 

I 

+ 62 

- 43 

+ 19 

+212 

- 80 

+ 132 

+ 190 

- 75 

+ 115 

+ 174 

- 67 

+ 107 

0 

0 

0 

0 

0 

0 

J 

+ 39 

- 57 

- 18 

+ 105 

- 80 

+ 25 

+ 97 

- 80 

+ 17 

+ 92 

- 80 

+ 12 

0 

0 

0 

0 

- 2 

- 2 

K 

+ 20 

- 93 

- 73 

+101 

-140 

- 39 

+ 94 

-140 

- 46 

+ 99 

-140 

- 41 

0 

0 

0 

0 

- 1 

- 1 

L 

+ 16 

-137 

-121 

+ 73 

-198 

-125 

+ 69 

-193 

-124 

+ 62 

-188 

-126 

0 

- 1 

- 1 

0 

- 7 

- 7 

M 

+ 15 

-351 

-336 

+ 53 

-473 

-420 

+ 43 

-452 

-409 

+ 44 

-450 

-406 

0 

-19 

- 19 

0 

-14 

- 14 

N 

+ 6 

-322 

-316 

+ 16 

-405 

-389 

+ 22 

-403 

-381 

+ 36 

-415 

-879 

0 

-95 

- 95 

0 

+ 15 

+ 15 

0 

+ 2 

-301 

-299 

0 

-308 

-308 

+ 13 

-316 

-803 

+ 31 

-330 

-299 

0 

-90 

- 90 

0 

+99 

+ 99 

18 



- 65 



- 57 



- 56 



- 55 



- 14 



+ 24 

17 



- 64 



— 60 



- 59 



— 68 



— 11 



+ 21 

16 



- 63 



- 61 



- 60 



— 59 



- 10 



+ 20 

15 



- 65 



- 60 



- 59 



— 68 



— 10 



+ 19 

14 



- 65 



- 54 



- 53 



- 52 



— 11 



+ 17 

13 



-107 



- 86 



- 84 



— 88 



- 21 



+ 25 

12 



- 62 



- 51 



- 51 



- 49 



- 18 



+ 23 

11 



- 36 



- 38 



- 88 



— 87 



- 8 



+ 21 

10 



- 12 



— 22 



- S3 



— 21 



0 



+ 14 

9 



+ 5 



— 1 



- 1 



- 1 



-f 4 



4- 10 

S 



+ 11 



+ 9 



+ 9 



+ 9 



+ 10 



+ 15 

7 



+ 7 



+ 6 



+ 6 



+ 6 



+ 6 



4- 10 

6 



+ 9 



+ 8 



+ 8 



+ 8 



+ 7 



4- 9 

5 



+ 9 



+ 8 



+ 8 



+ 8 



+ 8 



+ 9 

4 



+ 8 



+ 7 



+ 7 



+ 7 



+ 7 



+ 8 

3 



+ 5 



+ 4 



+ 4 



+ 4 



+ 3 



+ 5 

2 



+ 3 



+ 3 



+ 3 



+ 3 



+ 3 



4- 4 

1 



+ 1 



+ 1 



+ 1 



+ 1 



+ 1 



4- 1 



















Total. 



-414 



+382 



+313 



+281 



— 205 



+446 













































































































































































INVESTIGATIONS OP GRAVITY AND ISOSTASY, 


25 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

pensa- 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy- 

and 

com¬ 

pensa¬ 

tion 


Mount Hamilton, Cal., 

No. 55 

Seattle, Wash, (high school), 
No. 56 

Iron River, Mich., No. 57 

Ely, Minn., No. 58 

A 


+ 2 

o 

4- 

2 


+ 2 

o 

4- 2 

1500 

+ 2 

o 

4 - 2 

1470 

4- 9 

0 

4- 9 

B 


+ 68 

o 

4- 

68 


+44 

o 

4 - 44 

1500 

+ 64 

o 

4- 64 

1470 

4- 64 

0 

4. 64 

c 


-j-156 

o 

4- 

156 


+ 18 

o 

+ 18 

1500 

+ 124 

o 

4-124 

1470 

4-l?4 

0 

4-124 

D 


+246 

— 6 

J- 940 


+ 10 

o 

4 - io 

1500 

+ 138 

o 

4-138 

1470 

4-138 

0 

4-138 

E 


+282 

— 8 

4- 

274 


+ 3 

o 

4- 3 

1560 

+ 80 

o 

4 - 80 

1470 

4 . Kg 

0 

4 - 80 

F 


+194 

— 10 

4- 

184 


0 

o 

0 

1580 

+ 40 

0 

4- 40 

1470 

4 . 30 

0 

4- 30 

G 


+ 104 

— 12 

4- 

92 


0 

o 

0 

1580 

+ 12 

o 

4- 12 

1470 

4- 12 

0 

4- 12 

H 


+ 69 

— 16 

4- 

53 


0 

0 

0 

1580 

+ 16 

-16 

0 

1470 

4- 16 

16 

0 

I 


+ 53 

—20 

4- 

33 


0 

o 

0 

1590 

+ 20 

-20 

0 

1480 

4- 20 

20 

0 

J 


+ 32 

—25 

4- 

7 


0 

o 

o 

1580 

0 

—16 

— 16 

1.560 

0 

16 

16 

K 


+ 20 

—28 


8 


0 

o 

o 

1530 

0 

—20 

- 20 

1600 

0 

20 

20 

L 


0 

—18 


18 


0 

— 1 

— 1 

1580 

0 

-42 

- 42 

1580 

0 

—33 

— 33 

M 


0 

—24 


24 


0 

-19 

— 19 

1470 

0 

-84 

- 84 

1550 

0 

85 

— 85 

N 


0 

-16 


16 


0 

—95 

— 95 

1200 

0 

-63 

- 63 

1240 

0 

—69 

— 69 

0 


0 

0 


o 


0 

-89 

— 89 

890 

0 

-50 

- 50 

1180 

0 

-67 

— 67 

18 




4- 

2 




— u 




- 6 


— 12 

17 





2 




— 11 




- 6 




— 12 

16 





0 




— 10 




- 6 




— 12 

15 




4- 

2 




— 10 




- 7 




— 12 

14 




4- 

8 




— 11 




- 7 




— 11 

13 




4- 

22 




— 21 




- 18 




— 16 

12 




4- 

19 




- 18 




- 12 




— 13 

11 




4- 

20 




— 8 




- 9 




— 11 

10 




4- 

15 




0 




- 7 




— 10 

9 




4- 

10 




+ 4 




- 2 




— 5 

8 




4- 

15 




+ 10 




4- 8 




— 1 

7 




4- 

10 




+ 6 




+ 5 




4- 5 

6 




4- 

9 




+ 7 




+ 8 




+ 9 

5 




4- 

9 




+ 8 




+ 8 




+ 9 

4 




4- 

8 




+ 7 




+ 6 




4 - 6 

3 




4- 

5 




+ s 




+ 4 




+ 4 

2 




4- 

A 




4- 8 




+ 4 




+ 4 

1 




+ 

i 




+ / 




+ l 




+ i 
















Total 




4-1200 




-181 




+143 




+ 83 



















Pembina, N. Dak., No. 59 

Mitchell, S. Dak., No. 60 

Sweetwater, 

Tex., No. 61 

Kerrville, Tex., No. 62 

A 

796 

4* 2 

0 


+ 2 

1340 

4- 2 

0 

+ 2 

2149 

4- 2 

0 

4- 2 

1633 

4- 2 

0 

4* 2 

B 

796 

+60 

0 


+60 

1340 

+ 64 

0 

+ 64 

2150 

+ 68 

0 

+ 68 

1650 

+ 68 

0 

+ 68 

C 

796 

+88 

0 


+88 

1340 

+116 

0 

+116 

2150 

+ 136 

0 

+ 136 

1650 

+128 

0 

+128 

D 

796 

+60 

0 


+60 

1330 

+ 123 

0 

+ 123 

2160 

+191 

0 

+ 191 

1667 

+151 

0 

+151 

E 

796 

+24 

0 


+24 

1320 

+ 65 

0 

+ 65 

2160 

+156 

- 8 

+148 

1700 

+ 92 

0 

+ 92 

F 

796 

+10 

0 


+10 

1320 

+ 30 

0 

+ 30 

2156 

+ 79 

- 10 

+ 69 

1740 

+ 49 

- 4 

+ 45 

G 

796 

0 

0 


0 

1330 

+ 12 

0 

+ 12 

2130 

+ 37 

- 12 

+ 25 

1750 

+ 32 

- 12 

+ 20 

H 

796 

0 

0 


0 

1320 

+ 16 

-16 

0 

2140 

+ 32 

- 16 

+ 16 

1830 

+ 32 

- 16 

+ 16 

I 

796 

0 

0 


0 

1320 

+ 20 

-20 

0 

2200 

+ 20 

- 20 

0 

1835 

+ 20 

- 20 

0 

J 

800 

0 

-16 


-16 

1330 

0 

-16 

- 16 

2260 

0 

- 16 

- 16 

1930 

0 

- 16 

- 16 

K 

800 

0 

-20 


-20 

1330 

0 

-20 

- 20 

2280 

0 

- 24 

- 24 

1912 

0 

- 20 

- 20 

L 

800 

0 

-24 


-24 

1360 

0 

-28 

- 28 

2290 

0 

- 54 

- 54 

1900 

0 

- 48 

- 48 

M 

960 

0 

-52 


-52 

1410 

0 

-78 

- 78 

2150 

0 

-123 

-123 

1870 

0 

-107 

-107 

N 

990 

0 

-52 


-52 

1540 

0 

-80 

- 80 

2000 

0 

-100 

-100 

1460 

0 

- 76 

- 76 

0 

1100 

0 

-62 


-62 

1620 

0 

-89 

- 89 

2100 

0 

-107 

-107 

1210 

0 

- 64 

- 64 

18 





— 13 




- 18 




- 24 




- 12 

17 





— 13 




- 18 




- 22 




- 12 

16 





— 13 




— 18 




- 21 




- 11 

15 





—13 




- 19 




- 22 




- 13 

14 





—14 




- 19 




- 22 




- 12 

13 





—25 




— 31 




- 38 




- 23 

12 





— 14 




- 21 




- 21 




- 13 

44 





— 13 




- 24 




- u 




- 11 

10 





—15 




— 16 




- 11 




- 8 

9 





— 8 




- 10 




+ 2 




+ s 

g 





— 5 




- 5 




+ 8 




+ 8 

7 





4- 4 




+ 6 




+ 9 




+ 9 

g 





4-10 




+ 9 




+ 10 




+ 10 






4-10 




+ 11 




+ 10 




+ 10 

4 





4- 7 




+ 7 




+ 9 




+ 9 

3 





4- 3 




+ 4 




+ 6 




+ « 

2 





4- 4 




+ 3 




+ 3 




+ 2 

4 





4- l 




+ 1 




+ 1 




+ 1 



















Total 





—89 




- 57 




+ 93 




+133 
































































































































































































































































26 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd 


Zone 


A 

B 

C 

D 

E 

F 

G 

H 

1 
J 

K 

L 

M 

N 

O 

18 

17 

16 

15 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

Total.., 


A 

B 

C 

D 

E 

F 

G 

H 

1 

J 

K 

L 

M 

N 

O 

18 

17 

16 

15 

14 

13 

12 

11 

10 

9 

8 

7 

6 

5 

4 

3 

2 

1 

Total.., 


Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

El Paso, Tex., No. 63 

Nogales, Ariz., No. 64 

Yuma, Ariz., No. 65 

Compton, Cal., No. 66 

3760 

+ 2 

0 

4- 2 

3874 

4- 2 

0 

4" 2 

176 

+ 2 

0 

4- 2 

69 

+ 2 

0 

4- 2 

3760 

+ 68 

0 

+ 68 

3874 

+ 68 

0 

+ 68 

176 

+36 

0 

+36 

70 

+16 

0 

+ 16 

3770 

+156 

0 

+ 156 

3874 

+156 

0 

+ 156 

176 

+12 

0 

+ 12 

70 

+ 4 

0 

+ 4 

3770 

+268 

- 6 

+262 

3874 

+270 

- 6 

+264 

168 

+ 6 

0 

+ 6 

69 

0 

0 

0 

3800 

+292 

- 8 

+284 

3900 

+296 

- 8 

+288 

162 

0 

0 

0 

69 

0 

0 

0 

3865 

+187 

- 10 

+ 177 

3930 

+ 193 

- 10 

+ 183 

155 

0 

0 

0 

74 

0 

0 

0 

3880 

+ 98 

- 12 

+ 86 

3940 

+105 

- 12 

+ 93 

140 

0 

0 

0 

86 

0 

0 

0 

3910 

+ 61 

- 16 

+ 45 

3960 

+ 64 

- 16 

+ 48 

151 

0 

0 

0 

91 

0 

0 

0 

3960 

+ 60 

- 40 

+ 20 

3980 

+ 60 

- 40 

+ 20 

159 

0 

0 

0 

81 

0 

0 

0 

4070 

+ 32 

- 48 

- 16 

3820 

+ 32 

- 48 

- 16 

207 

0 

0 

0 

90 

0 

0 

0 

4030 

+ 20 

- 60 

- 40 

3900 

+ 20 

- 60 

- 40 

298 

0 

- 6 

- 6 

134 

0 

0 

0 

3910 

+ 24 

- 96 

- 72 

3600 

+ 14 

- 86 

- 72 

415 

0 

-12 

-12 

200 

0 

- 5 

- 5 

4200 

+ 16 

-242 

-226 

2890 

+ 9 

-171 

-162 

430 

0 

-28 

-28 

390 

0 

-25 

-25 

4200 

+ 6 

-216 

-210 

2875 

0 

-150 

-150 

470 

0 

-25 

-25 

1010 

0 

-50 

-50 

4570 

0 

-221 

-221 

2920 

0 

-148 

-148 

932 

0 

-48 

-48 

1130 

0 

-60 

- 60 




— 46 




- 30 




-17 




-10 




— 45 




- 24 




-17 




- 8 




— 44 




— 24 




. -18 




0 




— 48 




- 28 




-18 




+ 6 




— 49 




— 28 




-20 




+ 7 




— 75 




- 49 




-15 








— 32 




- 27 




- 9 




+14 




— 23 




- 12 




+ 3 




+ 9 




- 7 




0 




+ 3 




+ 13 




+ 3 




4- 6 




+10 




+11 




4- 14 




+ 15 




+ 16 




+16 




+ 5 




+ 8 




+ 10 




+11 




+ JO 




+ 9 




+ 9 




+ 9 




+ 10 




+ 9 




+ 9 




+ 9 




+ 9 




4- 8 




+ 8 




+ 8 




+ 6 




+ 5 




+ 5 




+ 5 




+ S 




+ 4 




+ 4 




+ 4 




+ 1 




+ 1 




+ 1 




+ i 


















+ 7 




+377 




-99 




+ 5 
















Goldfield, Nev., No. 67 

Yavapai, Ariz., No. 68 

Grand Canyon 

, Ariz., No. 69 

Gallup, N. Mex., No. 70 

5629 

4- 2 

0 

4- 2 

7150 

+ 2 

0 

+ 2 

2784 

+ 2 

0 

+ 2 

6496 

+ 2 

0 

+ 2 

5700 

+ 68 

0 

+ 68 

7150 

+ 68 

0 

+ 68 

2784 

+ 68 

0 

+ 68 

6496 

+ 68 

0 

+ 68 

5690 

+ 164 

- 4 

+ 160 

6800 

+ 126 

- 4 

+ 122 

2875 

+ 148 

0 

+148 

6496 

+ 164 

- 4 

+ 160 

5688 

+301 

- 6 

+295 

6440 

+267 

- 6 

+201 

3400 

+ 190 

- 5 

+ 185 

6496 

+318 

- 6 

+312 

5700 

+406 

- 12 

+394 

5850 

+391 

- 12 

+379 

3510 

+182 

- 8 

+174 

6600 

+440 

- 16 

+424 

5840 

+328 

- 20 

+308 

5210 

+339 

- 15 

+324 

3800 

+ 92 

- 10 

+ 82 

6660 

+390 

- 20 

+370 

5970 

+195 

- 24 

+ 171 

5560 

+247 

- 20 

+ 227 

4410 

+ 37 

- 16 

+ 21 

6720 

+242 

- 24 

+218 

5970 

+147 

- 32 

+ 115 

5320 

+ 177 

- 25 

+ 152 

4820 

+ 11 

- 23 

- 12 

6720 

+ 175 

- 32 

+143 

5975 

+ 113 

- 52 

+ 61 

5110 

+ 15S 

- 49 

+ 109 

5170 

+ 7 

- 48 

- 41 

6760 

+ 148 

- 60 

+ 88 

5990 

+ 51 

- 62 

- 11 

5510 

+ 85 

- 60 

+ 25 

5500 

+ 15 

- 61 

- 46 

6850 

+ 83 

- 79 

+ 4 

5610 

+ 51 

- 91 

- 40 

6240 

+ 79 

-105 

- 26 

6390 

- 6 

-106 

-112 

6960 

+ 75 

-120 

- 45 

5400 

+ 29 

-125 

- 96 

6460 

+ 49 

-156 

-107 

6280 

- 5 

-149 

-154 

7050 

+ 48 

-169 

-121 

5900 

0 

-313 

-313 

5930 

+ 51 

-345 

-294 

6150 

+ 2 

-359 

-357 

7190 

+ 34 

-417 

-383 

5480 

+ 16 

-293 

-277 

5950 

+ 17 

-306 

-289 

5950 

+ 7 

-306 

-299 

6820 

+ 16 

-359 

-343 

6210 

+ 1 

-302 

-301 

5200 

+ 9 

-265 

-256 

5200 

+ 9 

-265 

-258 

6410 

+ 9 

-321 

-312 




- 61 




- 56 




— 56 




— 63 




- 56 




- 53 




— 53 




— 63 




- 51 




- 48 




— A8 








- 41 




- 48 




— 18 




— 69 




- 40 




- 50 




— 50 




— 63 




- 61 




- 81 




— 81 




— 91 



. 

- 20 




- 56 




— 56 




— 47 




- 4 




- 25 




— 25 




— 32 




+ 5 




- 4 




— 4 




— 9 




+ 8 




+ 6 




4- 6 




4 - A 




+ 12 




+ 12 




4- 12 




4- IP, 




+ 9 




+ 8 




4- 8 




4- 7 




+ 9 




+ 9 




4- 9 




4 . o 




+ 9 




+ 9 




4- 9 




4 - n 




+ 8 




+ 8 




4- 8 




4 . s 




+ S 




4- 5 




. . 4 - 5 




4 - 5 




+ 4 




+ 3 




4- 3 




4 . * 




+ 1 




+ 1 




4- 1 




+ 1 



















+272 




+337 




-957 




+141 

































































































































































































































INVESTIGATION'S OF GRAVITY AND ISOSTASY. 27 

Mean elevations and corrections for topography and isostatic compensation,separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

petisa- 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Las Vegas, N. Mex., No. 71 

Shamrock, Tex., No 

.72 

Denison, Tex., No. 

73 

Minneapolis, Minn., No. 74 

A 

6429 

4 2 

0 

4 2 

2300 

“h 2 

0 

4 2 

754 

4 2 

0 

4 2 

840 

4 2 

0 

4 2 

B 

6429 

4 68 

0 

4 68 

2300 

4 68 

0 

4 68 

754 

460 

0 

460 

840 

460 

0 

460 

C 

6429 

+ 164 

- 4 

4160 

2300 

4140 

0 

4140 

740 

484 

0 

484 

840 

492 

0 

492 

D 

6429 

4318 

- 6 

4312 

2300 

4198 

0 

4198 

740 

454 

0 

454 

830 

464 

0 

464 

E 

6400 

4440 

- 10 

4424 

2300 

4168 

- 8 

4160 

730 

424 

0 

424 

820 

424 

0 

424 

F 

6460 

4381 

- 20 

4361 

2300 

4 90 

- 10 

4 80 

690 

410 

0 

410 

840 

410 

0 

410 

G 

6530 

4241 

- 24 

4217 

2300 

4 48 

- 12 

4 36 

660 

0 

0 

0 

880 

0 

0 

0 

H 

6560 

4109 

- 32 

4137 

2300 

4 32 

- 16 

4 16 

690 

0 

0 

0 

890 

0 

0 

0 

I 

6680 

4148 

- 60 

4 88 

2350 

4 20 

- 20 

0 

650 

0 

0 

0 

880 

0 

0 

0 

J 

6800 

4 85 

- 79 

4 6 

2390 

4 4 

- 20 

- 16 

690 

0 

-16 

-16 

880 

0 

-16 

-16 

K 

6850 

4 78 

-120 

- 42 

2425 

4 13 

- 40 

- 27 

670 

0 

-20 

-20 

900 

0 

-20 

-20 

L 

7100 

4 43 

-171 

-128 

2420 

4 4 

— 5(5 

- 52 

700 

0 

-24 

-24 

920 

0 

-24 

-24 

M 

7100 

4 35 

-412 

-377 

2300 

0 

-128 

-128 

680 

0 

-37 

-37 

990 

0 

-56 

-56 

N 

6650 

4 21 

-350 

-329 

2260 

0 

-115 

-115 

710 

0 

-42 

-42 

1000 

0 

-48 

-48 

0 

6140 

4 12 

-309 

-297 

2410 

0 

-122 

-122 

700 

0 

—45 

-45 

1040 

0 

-56 

-56 

18 




- 62 




- 24 




- 9 




—12 

17 




- 62 




- 24 




- 9 




—12 

16 




- 62 




- 24 




- 9 




— 12 

15 




- 59 




- 24 


:::::::: 


— 9 




— 13 

14 




- 61 




- 25 




- 9 




—13 

13 




- 89 




- 44 




—20 




—21 

12 




- 43 




— 25 




—13 




-15 

11 




- 26 




- 17 




-11 




— 12 

10 




- 18 




- 4 




— 12 




— 9 

9 




- 1 




- 1 




- 3 




— 6 

8 




4 9 




4 6 




+ 3 




0 

7 




4 7 




4 8 




4 8 




4 6 

6 




4 9 




4 10 




4 9 




4 9 

5 




4 tO 




4 10 




+ 11 




4 10 

4 




4 S 




4 9 




4 8 




4 6 

3 




4 5 




4 6 




4 5 




4 4 

2 




+ 3 




4 2 




4- 3 




4- 4 

1 




4 1 




4 1 




4 1 




4 1 
















Total.. 




4171 




4 70 




- 6 




-52 


















Lead, S. Dak., No. 

75 

Bismarck, N. Dak., No. 76 

Hinsdale, Mont., No. 77 

Sand Point, Idaho, No. 78 

A 

5216 

4- 2 

0 

4 2 

1690 

4" 2 

0 

4 2 

2170 

4- 2 

0 

4 2 

2090 

4 2 

0 

4 2 

B 

5200 

4 64 

0 

4 64 

1690 

4 68 

0 

4 68 

2170 

4 68 

0 

4 68 

2090 

4 68 

0 

4 68 

C 

5200 

4164 

- 4 

4160 

1690 

4128 

0 

4128 

2160 

4140 

0 

4140 

2100 

4136 

0 

4136 

D 

5200 

4300 

- 6 

4294 

1700 

4156 

0 

4156 

2160 

4190 

0 

4190 

2100 

4186 

0 

4186 

E 

5290 

4386 

- 8 

4378 

1700 

4 98 

0 

4 98 

2170 

4155 

- 8 

4147 

2080 

4148 

- 8 

4140 

F 

5300 

4296 

- 20 

4276 

1720 

4 49 

- 5 

4 44 

2210 

4 80 

- 10 

4 70 

2050 

4 73 

- 10 

4 63 

G 

5420 

4182 

- 24 

4158 

1730 

4 24 

- 6 

4 18 

2270 

4 38 

- 12 

4 26 

2080 

4 36 

- 12 

4 24 

H 

5550 

4131 

- 32 

4 99 

1710 

4 22 

- 16 

4 6 

2330 

4 17 

- 16 

4 1 

2230 

4 26 

- 16 

4 10 

I 

5600 

4 83 

- 40 

4 43 

1730 

4 20 

- 20 

0 

2350 

4 20 

- 20 

0 

2510 

4 15 

- 20 

- 5 

J 

5260 

4 45 

- 48 

- 3 

1780 

0 

- 16 

- 16 

2360 

0 

- 16 

- 16 

2720 

4 16 

- 32 

- 16 

K 

5040 

4 45 

- 80 

- 35 

1820 

0 

- 20 

- 20 

2320 

0 

- 25 

- 25 

2900 

0 

- 43 

- 43 

L 

4840 

4 32 

-120 

- 88 

1880 

0 

- 48 

- 48 

2390 

0 

- 54 

- 54 

3100 

+ 1 

- 72 

- 71 

M 

4400 

4 27 

-260 

-233 

2000 

0 

-112 

-112 

2650 

0 

-149 

-149 

3S90 

4 11 

-238 

-227 

N 

3890 

0 

-199 

-199 

2010 

0 

- 96 

- 96 

2790 

0 

-145 

-145 

3970 

0 

-204 

-204 

O 

3610 

0 

-174 

-174 

2020 

0 

-105 

-105 

2890 

0 

-135 

-135 

4110 

0 

-205 

-205 

18 




— 36 




— 20 




- 31 




- 42 

17 




— 37 




- 20 




- 31 




- 42 

16 




— 37 




- 19 




- 31 




- 40 

15 




- 39 




— 20 




- 32 




- 40 

14 




- 40 




- 20 




- 33 




- 40 

13 




— 61 




- 38 




- 66 




- 70 

12 




— 35 




- 26 




- 40 




— 39 

11 




— 30 




- 23 




- 30 




- 21 

10 




- 19 




- 17 




- 21 




- 11 

9 




— 6 




- 10 




- 13 




0 

s 




4 1 




- 3 




4 2 




4 7 

7 




4 6 




4 5 




4 5 




4 6 

6 




4 9 




4 9 




4 10 




4 8 

5 




4 10 




4 10 




4 9 




4 8 

4 




4 7 




4 7 




4 7 




4 7 

3 



1 

4 4 




4 4 




4 3 




4 3 

2 




+ 3 




4 3 




4 4 




4 3 

i 




4 / 




4 1 




4 i 




4 1 





















4443 




- 54 




-167 




-444 










































































































































































































































28 TJ. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and" 

com¬ 

pensa¬ 

tion 


Boise, Idaho, No. 

79 

Astoria, Oreg., No. 

80 

Sisson, Cal., No. 81 

Rock Springs, Wyo., No. 82 

A 

2690 

•+• 2 

0 

4- 2 

5 

+1 

0 

+ 1 

3440 

+ 2 

0 

+ 2 

6260 

4- 2 

0 

+ 2 

B 

2690 

+ 68 

0 

+ 68 

5 

0 

0 

0 

3440 

+ 68 

0 

+ 68 

6260 

+ 68 

0 

+ 68 

C 

2690 

+ 148 

0 

+ 148 

15 

0 

0 

0 

3420 

+ 151 

0 

+ 151 

6250 

+ 164 

- 4 

+160 

D 

2700 

+222 

0 

+222 

50 

-5 

0 

- 5 

3400 

+ 259 

- 6 

+253 

6270 

+315 

- 6 

+309 

E 

2720 

+201 

- 8 

+ 193 

120 

-1 

0 

- 1 

3390 

+264 

- 8 

+256 

6290 

+ 433 

- 16 

+ 417 

F 

2760 

+111 

- 10 

+ 101 

50 

0 

0 

0 

3640 

+ 169 

- 10 

+ 159 

6360 

+370 

- 20 

+350 

G 

2830 

+ 60 

- 12 

+ 48 

20 

0 

0 

0 

3790 

+ 84 

- 12 

+ 72 

6420 

+ 234 

- 24 

+210 

H 

2930 

+ 41 

- 16 

+ 25 

20 

0 

0 

0 

3890 

+ 48 

- 16 

+ 32 

6510 

+ 161 

- 32 

+129 

I 

3120 

+ 18 

- 20 

- 2 

20 

0 

0 

0 

4550 

+ 35 

- 40 

- 5 

6700 

+ 146 

- 60 

+ 86 

J 

3440 

+ 18 

- 32 

- 14 

80 

0 

0 

0 

5450 

+ 16 

- 48 

- 32 

6540 

+ 89 

- 80 

+ 9 

K 

3560 

+ 5 

- 60 

- 55 

90 

0 

0 

0 

5260 

+ 2 

- 80 

- 78 

6610 

+ 80 

-120 

- 40 

L 

3560 

- 4 

- 81 

- 85 

190 

0 

- 4 

- 4 

4610 

+ 8 

-111 

-103 

6880 

+ 43 

-163 

-120 

M 

3S80 

+ 8 

-231 

-223 

410 

0 

—23 

-23 

4250 

+ 11 

-252 

-241 

7020 

+ 56 

-406 

-350 

N 

4410 

+ 7 

-234 

-227 

- 40 

0 

+ 4 

+ 4 

4010 

0 

-205 

-205 

7180 

+ 15 

-378 

-363 

O 

4790 

+ 8 

-241 

-233 

-552 

0 

+29 

+29 

3510 

0 

-174 

-174 

7730 

+ 6 

-377 

-371 

18 




— 53 




+ 3 




— 29 




— 73 

17 




— 56 




0 




— 25 




— 71 

16 




- 56 




+ 3 




— 21 




— 71 

15 




- 54 




+ 5 




— 17 




— 73 

14 




— 52 




+ 3 




— 7 




— 67 

13 




— 80 




0 




— 2 




— 99 

12 




— 57 




~ 1 




-f 8 




— 55 

11 




- 24 




-h 8 




4 - 12 




— 38 

10 




- 8 




+ 6 




4- 9 




— 16 

9 




+ 2 




+ 6 




-j- 8 




4- 2 

8 




+ 9 




+ 11 




4- 18 




4- 10 

7 




+ 7 




+ 7 




4- 9 




4 - 7 

6 




+ 8 




+ 7 




8 




4- 9 

5 




+ 8 




+ 8 




4 . 9 




4- 9 

4 




+ 7 




+ 7 




4- 8 




4- 8 

3 




+ 4 




+ 3 




4- A 




+ 5 

2 


:::::::: 


4- 8 




4- 8 




4- A 




4 - 3 

1 



. 

+ i 




+1 




+ i 




4 - i 
















Total.. 




—423 




+76 




+147 




- 13 
















Paxton, Nebr., No. 83 


Washington, D. C. (Bureau of 
Standards), No. 84 


North Hero, Vt., No. 85 


Lake Placid, N. Y., No. 86 


A 

3060 

+ 2 

0 

+ 2 


+ 2 

0 

+ 2 

115 

+ 2 

0 

+ 2 

1870 

4- 2 

0 

+ 2 

B 

3060 

+ 68 

0 

+ 68 


+ 48 

0 

+ 48 

115 

+24 

0 

+24 

1870 

+ 68 

0 

+ 68 

C 

3060 

+152 

0 

+152 


+32 

0 

+ 32 

115 

+ 4 

0 

+ 4 

1880 

+ 136 

0 

+ 136 

D 

3070 

+243 

- 3 

+240 


+ 16 

0 

+ 16 

120 

+ 6 

0 

+ 6 

1890 

+ 170 

0 

+ 170 

E 

3080 

+236 

- 8 

+228 


+ 8 

0 

+ 8 

110 

0 

0 

0 

1860 

+ 119 

- 3 

+116 

F 

3110 

+140 

- 10 

+ 130 


0 

0 

0 

110 

0 

0 

0 

1920 

+ 59 

- 7 

+ 52 

G 

3120 

+ 72 

- 12 

+ 60 


0 

0 

0 

100 

0 

0 

0 

1930 

+ 37 

-12 

+ 25 

H 

3110 

+ 48 

- 16 

+ 32 


0 

0 

0 

100 

0 

0 

0 

2020 

+ 22 

- 7 

+ 15 

I 

3120 

+ 20 

- 20 

0 


0 

0 

0 

110 

0 

0 

0 

2320 

+ 11 

-20 

- 9 

J 

3170 

+ 16 

- 32 

- 16 


0 

- 1 

- 1 

110 

0 

0 

0 

2406 

+ 8 

-24 

- 16 

K 

3210 

0 

- 40 

- 40 


0 

- 1 

- 1 

150 

0 

0 

0 

2260 

+ 6 

-40 

- 34 

L 

3270 

0 

- 72 

- 72 


0 

- 2 

- 2 

260 

0 

- 3 

- 3 

2050 

0 

-50 

- 50 

M 

3250 

+ 13 

-196 

-183 

........ 

0 

-15 

- 15 

660 

0 

-32 

-32 

1380 

0 

-75 

- 75 

N 

3270 

0 

-170 

-170 


0 

-19 

- 19 

680 

0 

-44 

-44 

980 

0 

-52 

- 52 

O 

3280 

0 

-155 

-155 


0 

-25 

- 25 

680 

0 

-48 

-48 

700 

0 

-41 

- 41 

18 




- 33 




- 5 




— ID 




10 

17 




- 34 




- 8 




10 




q 

16 




- 33 




- 9 




— 11 




q 

15 




- 33 




— 8 




— 7 




8 

14 




- 33 




— 4 




— 7 




7 

13 




- 59 




4- 2 




16 




18 

12 




- 38 




+ 13 




— 6 




8 

11 




- 26 




+ 18 




4 - 8 





10 




- 17 




+ 17 




4 -// 




-t- 4 

4- 11 

9 




- 4 




+ 11 




4 -in 




4- Q 

8 




+ 3 




+ 12 




A -11 




4- 11 

7 




+ 7 




4- 6 




4- R 





6 




+ 9 




4- 6 




4- 6 





5 




+ 10 




+ 7 




-4- 7 




4- 7 

4 




+ 8 




4- 6 




4> 6 





3 




+ 5 




4* 6 




4 - 6 





2 




+ 8 




+ 4 




4- 5 





1 




+ 1 




+ l 




+ 1 




+ i 















Total.. 




+ 17 




+118 




-86 




+320 


























































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 29 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Potsdam, N. Y., No. 87 

Wilson, N 

Y., No. 88 

Alpena, Mich., No. 89 

Virginia Beach, Va., No. 90 

A 

430 

+ 2 

0 

+ 2 

280 

4- 2 

0 

+ 2 

585 

+ 2 

0 

+ 2 

12 

+ 2 

0 

+ 2 

B 

430 

+56 

0 

+56 

280 

+ 48 

0 

+48 

580 

+56 

0 

+56 

12 

0 

0 

0 

C 

430 

+52 

0 

+52 

280 

+28 

0 

+28 

580 

+68 

0 

+68 

3 

0 

0 

0 

D 

440 

+22 

0 

+ 22 

280 

+ 12 

0 

+ 12 

580 

+42 

0 

+ 42 

2 

0 

0 

0 

E 

420 

+ 8 

0 

+ 8 

280 

+ 8 

0 

+ 8 

580 

+ 16 

0 

+ 16 

4 

0 

0 

0 

F 

430 

0 

0 

0 

270 

0 

0 

0 

580 

0 

0 

0 

2 

0 

0 

0 

G 

470 

0 

0 

0 

280 

0 

0 

0 

580 

0 

0 

0 

2 

0 

0 

0 

n 

475 

0 

0 

0 

270 

0 

0 

0 

580 

0 

0 

0 

0 

0 

0 

0 

i 

527 

0 

0 

0 

290 

0 

0 

0 

590 

0 

0 

0 

- 3 

0 

0 

0 

j 

600 

0 

-13 

-13 

270 

0 

0 

0 

590 

0 

-16 

-16 

-10 

0 

0 

0 

K 

577 

0 

-17 

-17 

300 

0 

0 

0 

590 

0 

-20 

-20 

-11 

0 

0 

0 

L 

635 

0 

-18 

-18 

350 

0 

- 8 

- 8 

590 

0 

-24 

-24 

-20 

0 

0 

0 

M 

746 

0 

-40 

-40 

350 

0 

-20 

-20 

640 

0 

-35 

-35 

-15 

0 

0 

0 

N 

810 

0 

-47 

-47 

580 

0 

-33 

-33 

660 

0 

-36 

-36 

-24 

0 

0 

0 

O 

680 

0 

-42 

-42 

850 

0 

-46 

-46 

660 

0 

-34 

-34 

-98 

0 

+5 

+ 5 

18 




- 8 




— 9 




— 7 




+ 7 

17 




- 8 




— 10 




— 7 




+ 11 

16 




- 9 




— 9 




— 7 




+ 12 

15 




- 8 




—10 




_ 7 




+ 16 

14 




- 9 




-10 




— 8 




+ SI 

13 




-16 




-IS 




—15 




+ S8 

12 




- 5 




— s 




— 10 




+ SO 

11 




+ 1 




— 1 




— 5 




+ 57 

10 




+ 8 




+ 5 




— 1 




+ 18 

9 




+ 7 




+ 6 




+ / 




+ IS 

8 




+ 11 




+ 10 




4- 6 




+ U 

7 




+ 7 




+ 7 




+ 6 




+ 6 

6 




+ 6 




4- 6 




+ 7 




+ 6 

5 




+ 6 




+ 6 




+ 7 




+ 7 

4 




+ 5 




+ 6 




+ 5 




+ 7 

3 




+ 6 




4- 6 




+ 6 




+ 6 

2 




+ 6 




+ 5 




+ 5 




+ s 

1 




+ 1 




+ 1 




+ 1 




+ 1 
















Total 




-37 




—18 




- 5 




+249 



















Durham, N. C., No. 91 

Femandina, 

Fla., No. 92 

Wilmer, Ala., No. 93 

Aliceville, Ala., No. 

94 

A 

413 

+ 2 

0 

+ 2 

10 

+2 

0 

+ 2 

226 

+ 2 

0 

+ 2 

242 

+ 2 

0 

+ 2 

B 

413 

+56 

0 

+ 56 

10 

0 

0 

0 

226 

+42 

0 

+ 42 

242 

+44 

0 

+44 

C 

413 

+43 

0 

+ 48 

10 

0 

0 

0 

226 

+20 

0 

+ 20 

244 

+24 

0 

+24 

T) 

413 

+ 18 

0 

+ 18 

7 

0 

0 

0 

226 

+ 12 

0 

+ 12 

246 

+ 12 

0 

+ 12 

E 

413 

+ 8 

0 

+ 8 

2 

0 

0 

0 

226 

+ 8 

0 

+ 8 

247 

+ 8 

0 

+ 8 

F 

413 

0 

0 

0 

7 

0 

0 

0 

226 

0 

0 

0 

245 

0 

0 

0 

G 

416 

0 

0 

0 

4 

0 

0 

0 

213 

0 

0 

0 

245 

0 

0 

0 

H 

415 

0 

0 

0 

- 3 

0 

0 

0 

213 

0 

0 

0 

248 

0 

0 

0 

I 

428 

0 

0 

0 

- 2 

0 

0 

0 

217 

0 

0 

0 

248 

0 

0 

0 

J 

426 

0 

0 

0 

0 

0 

0 

0 

219 

0 

0 

0 

247 

0 

0 

0 

K 

439 

0 

- 5 

- 5 

- 3 

0 

0 

0 

217 

0 

0 

0 

249 

0 

0 

0 

L 

437 

0 

- 5 

- 5 

-15 

0 

0 

0 

172 

0 

0 

0 

251 

0 

0 

0 

M 

444 

0 

-26 

- 26 

-10 

0 

0 

0 

131 

0 

-7 

- 7 

255 

0 

-14 

-14 

N 

401 

0 

-24 

- 24 

- 2 

0 

0 

0 

94 

0 

-5 

- 5 

269 

0 

-17 

-17 

0 

447 

0 

-20 

- 20 

-38 

0 

0 

0 

71 

0 

0 

0 

323 

0 

-18 

-18 

18 




— 5 




+ 2 




0 




- 4 

17 




— 7 




+ 3 




+ 1 




- 4 

16 




_ 7 




+ 4 




+ 2 




- 4 

1 D 




— i 




+ 5 




+ 5 




- 4 

14 




_ 1 




+ 7 




+ 7 




- 4 

13 




-f # 




+ 18 




+ 15 




- 1 

19 




4 - it 




+ 55 




+ u 




+ 5 

11 




4 - 18 




+ 54 




+ 7 




+ s 

in 




+ 19 




+ so 




+ 6 




+ 6 

Q 




+ 19. 




+ IS 




+ 5 




+ 3 

Q 




4" 11 




+ n 




+ 6 




+ 4 

7 




-f 5 




+ 5 




+ 7 




+ 7 

A 




4* 6 




+ 7 




+ 9 




+ 8 

r 




4- 8 




+ 9 




+ 10 




+11 

4 




4- 7 




+ 7 




+ 8 




+ 7 

9 




4- 6 




+ 6 




+ 6 




+ 6 

O 




4- 8 




+ s 




+ 3 




+ s 

1 




+ i 




+ 1 




+ 1 




+ 1 




















+ 144 




+170 




+181 




+80 





































































































































































































































30 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


New Madrid 

, Mo., No. 95 

Mena, Ark., No. 96 

Nacogdoches, Tex., No. 97 

Alpine, Tex., No. 98 

A 

258 

+ 2 

0 

+ 2 

1209 

+ 2 

0 

+ 2 

303 

+ 2 

0 

+ 2 

4460 

+ 2 

0 

+ 2 

B 

258 

+44 

0 

+44 

1209 

+ 64 

0 

+ 64 

300 

+48 

0 

+48 

4460 

+ 68 

0 

+ 68 

C 

258 

+24 

0 

+24 

1209 

+ 112 

0 

+ 112 

300 

+32 

0 

+32 

4460 

+ 164 

- 4 

+160 

D 

258 

+ 12 

0 

+ 12 

1200 

+ 108 

0 

+ 108 

300 

+ 12 

0 

+ 12 

4470 

+288 

- 6 

+282 

E 

260 

+ 8 

0 

+ 8 

1119 

+ 56 

0 

+ 56 

300 

+ 8 

0 

+ 8 

4500 

+344 

- 8 

+336 

F 

260 

0 

0 

0 

1120 

+ 22 

0 

+ 22 

300 

0 

0 

0 

4550 

+240 

- 10 

+230 

G 

260 

0 

0 

0 

1175 

+ 3 

0 

+ 3 

300 

0 

0 

0 

4520 

+ 129 

- 12 

+ 117 

11 

259 

0 

0 

0 

1247 

+ 4 

- 4 

0 

300 

0 

0 

0 

4540 

+ 80 

- 16 

+ 64 

1 

288 

0 

0 

0 

1205 

+ 5 

- 5 

0 

300 

0 

0 

0 

4730 

+ 67 

- 40 

+ 27 

J 

288 

0 

0 

0 

1222 

0 

-16 

- 16 

291 

0 

0 

0 

4960 

+ 34 

- 48 

- 14 

K 

290 

0 

0 

0 

1192 

0 

-20 

- 20 

281 

0 

0 

0 

4910 

+ 37 

- 80 

- 43 

L 

290 

0 

0 

0 

1169 

0 

-27 

- 27 

267 

0 

0 

0 

4800 

+ 23 

-115 

- 92 

M 

305 

0 

-14 

-14 

902 

0 

-51 

- 51 

286 

0 

-14 

-14 

4660 

+ 22 

-275 

-253 

N 

388 

0 

-27 

-27 

688 

0 

-37 

- 37 

306 

0 

-19 

-19 

4100 

+ 4 

-214 

-210 

O 

506 

0 

-30 

-30 

700 

0 

-37 

- 37 

259 

0 

-13 

-13 

3200 

0 

-153 

-153 

IS 




- 6 




- 7 




- 3 




— 28 

17 




— 6 




- 7 




- 3 




— 30 

16 




— 6 




— 7 




- 3 




— 30 

15 




- 6 




— 7 




- 2 




— 32 

14 




- 7 




— 7 




- 1 




.. — 32 

13 




-12 




— 13 




- 3 




— 55 

12 




- 8 




- 10 




- 2 




— U 

11 




- 5 




— 9 




- 4 




— 19 

10 




0 




— 7 




- 7 




— 6 

9 




- 1 




- 4 




- 1 




+ 3 

8 




+ 3 




+ 2 




+ 5 




+ IS 

7 




+ 7 




+ 8 




+ 8 




+ 6 

6 




+ 8 




+ 9 




+ 10 




+ 10 

5 




+ 10 




+ 11 




+ 10 




+ 10 

4 




+ 7 




+ 8 




+ 8 




+ 9 

3 




+ 6 




+ 6 




+ 6 




+ 6 

2 




+ 3 




+ 3 




+ 2 




4 - 3 

1 




+ 1 




+ l 




+ 1 




+ 1 
















Total.. 




+ 7 




+ 148 




+77 




+326 
















Farwell, Tex., No. 99 

Guymon, Okla., No. 100 

Helen wood, Tenn., No. 101 

Cloudland, Tenn., No. 102 

A 

4130 

4- 2 

0 

4- 2 

3000 

+ 2 

0 

+ 2 

1386 

4- 2 

0 

+ 2 

6200 

+ 2 

0 

+ 2 

B 

4130 

+ 68 

0 

+ 68 

3100 

+ 68 

0 

+ 68 

1386 

+ 64 

0 

+ 64 

6200 

+ 68 

0 

+ 68 

C 

4130 

+ 158 

- 2 

+ 156 

3100 

+ 152 

0 

+ 152 

1400 

+ 120 

0 

+ 120 

6100 

+ 164 

- 4 

+ 160 

D 

4130 

+282 

- 6 

+276 

3100 

+243 

- 3 

+240 

1400 

+ 132 

0 

+ 132 

5800 

+296 

- 6 

+ 290 

E 

4125 

+314 

- 8 

+306 

3050 

+236 

- 8 

+228 

1419 

+ 75 

0 

+ 75 

5450 

+408 

- 11 

+ 397 

F 

4125 

+213 

- 10 

+203 

3050 

+ 135 

- 10 

+ 125 

1470 

+ 36 

0 

+ 36 

5040 

+336 

- 15 

+ 321 

G 

4125 

+ 114 

- 12 

+ 102 

3050 

+ 72 

- 12 

+ 60 

1520 

+ 12 

0 

+ 12 

4480 

+ 196 

- 15 

+ 181 

H 

4125 

+ 64 

- 16 

+ 48 

3050 

+ 48 

- 16 

+ 32 

1440 

+ 16 

- 16 

0 

3980 

+ 127 

- 18 

+ 109 

I 

4125 

+ 60 

- 40 

+ 20 

3050 

+ 20 

- 20 

0 

1450 

+ 20 

- 20 

0 

3680 

+ 114 

- 35 

+ 79 

J 

4144 

+ 32 

- 48 

- 16 

3080 

+ 16 

- 32 

- 16 

1430 

0 

- 16 

- 16 

3470 

+ 55 

- 41 

+ 14 

K 

4150 

+ 20 

- 60 

- 40 

3180 

0 

- 40 

- 40 

1570 

0 

- 20 

- 20 

3150 

+ 44 

- 43 

+ 1 

L 

4150 

+ 24 

- 96 

- 72 

3430 

0 

- 72 

- 72 

1610 

0 

- 45 

- 45 

2830 

+ 21 

— 65 

- 44 

M 

4170 

+ 15 

-249 

-234 

3490 

+ 14 

-210 

-196 

1430 

0 

- 80 

- 80 

2340 

+ 18 

-135 

- 117 

N 

4190 

+ 3 

-220 

-217 

3390 

0 

-176 

-176 

1170 

0 

- 59 

- 59 

2000 

+ 7 

-100 

- 93 

O 

3920 

0 

-194 

-194 

3480 

0 

-167 

-167 

1280 

0 

- 68 

- 68 

1680 

0 

- 91 

- 91 

18 




- 41 




— 34 




— 13 




— 14 

17 




- 42 




- 34 




..— 14 




— 12 

16 




- 43 




— 34 




— 12 




— 10 

15 




- 43 




— 34 




- 8 




— 10 

14 




- 44 




- 36 




— 6 




— 6 

13 




- 67 




- 60 




— 9 




— 7 

12 




- 34 




— 32 




— 2 




4- 3 

11 




- 21 




— 21 




+ 4 




-f 9 

10 




- 15 




— 15 




+ 9 




4- ih 

9 




0 




— 1 




+ 6 




4- 9 

8 




+ 9 




+ 7 




+ 6 




+ 8 

7 




+ 8 




+ 8 




+ 6 




4- 6 

6 




+ 9 




+ 10 




+ 7 




4- 7 

5 




+ 10 




+ 10 




+ io 




+ 10 

4 




+ 8 




+ 9 




+ 7 




4- *7 

3 




+ 6 




+ 6 




+ 6 




+ 6 

2 




+ 3 




+ 2 




+ 3 




-j- 8 

1 




+ 1 




+ 1 




+ 1 




+ i 















Total.. 




+ 111 




- 8 




+154 




+ 1302 






































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 31 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Hughes, Tenn., No. 103 

Charleston, W. Va., No. 104 

State College, Pa., No. 105 

Fort Kent, 

He., No. 

106 

A 

3260 

+ 2 

0 

4~ 2 

602 

4- 2 

0 

+ 2 

1174 

+ 2 

0 

+ 2 

524 

+ 2 

0 

+ 2 

B 

3260 

+ 68 

0 

+ 68 

602 

+56 

0 

+56 

1174 

+ 64 

0 

+ 64 

525 

+56 

0 

+56 

C 

3220 

+ 152 

0 

+ 152 

602 

4-72 

0 

+72 

1180 

+ 112 

0 

+ 112 

525 

+60 

0 

+60 

D 

3350 

+255 

- 6 

+249 

625 

+39 

0 

+39 

1165 

+ 103 

0 

+ 103 

525 

+30 

0 

+30 

E 

3450 

+ 250 

- 8 

+ 242 

630 

+ 14 

0 

+ 14 

1160 

+ 55 

0 

+ 55 

525 

+ 16 

0 

+16 

F 

3720 

+ 154 

- 10 

+ 144 

785 

4- 8 

0 

+ 8 

1130 

+ 20 

0 

+ 20 

525 

0 

0 

0 

G 

4060 

4- 73 

- 12 

+ 61 

855 

0 

0 

0 

1135 

0 

0 

0 

525 

0 

0 

0 

H 

4060 

+ 42 

- 21 

+ 21 

880 

0 

0 

0 

1165 

0 

0 

0 

525 

0 

0 

0 

I 

3840 

+ 31 

- 33 

- 2 

920 

0 

0 

0 

1298 

+ 10 

-10 

0 

525 

0 

0 

0 

J 

3490 

+ 24 

- 40 

- 16 

985 

0 

-16 

-16 

1290 

0 

-16 

- 16 

525 

0 

- 8 

- 8 

K 

3250 

4* 6 

- 45 

- 39 

980 

0 

-20 

-20 

1340 

0 

-20 

- 20 

525 

0 

-10 

-10 

L 

. 3000 

+ 10 

- 72 

- 62 

980 

0 

-24 

-24 

1475 

0 

-40 

- 40 

530 

0 

-12 

-12 

M 

2340 

+ 6 

-138 

-132 

1140 

0 

-62 

-62 

1310 

0 

-75 

- 75 

750 

0 

-35 

-35 

N 

2000 

0 

- 98 

- 98 

1220 

0 

-64 

-64 

1230 

0 

-64 

- 64 

830 

0 

-47 

-47 

O 

1680 

0 

- 87 

- 87 

1670 

0 

-86 

-86 

1290 

0 

-73 

- 73 

670 

0 

-44 

-44 

18 




- 14 




—18 




— 12 




8 

17 




— 12 




—18 




— 11 




— 8 

16 




— 12 




— 14 




— 10 




— 8 

15 




- 10 




— 12 




— 8 




— 6 

14 




- 5 




— 10 




— 6 




— 7 

13 




- 7 




-11 




— S 




—28 

12 




+ 3 




- 1 




+ 6 




—15 

11 




+ 9 




+ 5 




+ 9 




4- 2 

10 




+ U 




+ 10 




+ 12 




+13 

9 




+ 9 




+ 8 




+ 8 




4-12 

S 




+ S 




4- 8 




+ 11 




+12 

7 




+ 6 




+ 5 




+ 6 




+ 6 

6 




+ 7 




+ 6 




+ 6 




-f 6 

5 




+ 10 




+ 8 




+ 7 




4- 6 

4 




+ 7 




+ 7 




+ 6 




4- 6 

3 




+ 6 




+ 6 




+ 6 




4- 6 

2 




+ 3 




+ 3 




4- 4 




4- 6 

1 




+ 1 




+ 1 




+ i 




4- 1 









’ * 







Total.. 




+ 526 




-98 




+ 100 




+ 9 


















Prentice, Wis., No. 107 

Fergus Falls, Minn., No. 108 

Sheridan, Wyo., No. 109 

Boulder, Mont., No. 110 

A 

1539 

+ 2 

0 

4- 2 

1200 

+ 2 

0 

+ 2 

3773 

+ 2 

0 

+ 2 

4898 

+ 2 

0 

+ 2 

B 

1539 

+ 68 

0 

+ 68 

1200 

+ 64 

0 

+ 64 

3773 

+ 68 

0 

+ 68 

4900 

+ 68 

0 

+ 68 

C 

1539 

+ 124 

0 

+ 124 

1200 

+ 112 

0 

+ 112 

3760 

+ 158 

- 2 

+ 156 

4900 

+ 164 

- 4 

+ 160 

D 

1500 

+ 138 

0 

+ 138 

1200 

+ 108 

0 

+ 108 

3768 

4" 270 

- 6 

+264 

4900 

+ 300 

- 6 

+ 294 

E 

1500 

+ 80 

0 

+ 80 

1200 

+ 56 

0 

+ 56 

3812 

+ 291 

- 8 

+ 283 

4900 

+ 364 

- 8 

+356 

F 

1500 

+ 30 

0 

+ 30 

1200 

+ 20 

0 

+ 20 

3840 

+ 182 

- 10 

+ 172 

5000 

+268 

- 18 

+ 250 

G 

1500 

+ 12 

0 

+ 12 

1200 

0 

0 

0 

3883 

+ 96 

- 12 

+ 84 

5117 

+ 106 

- 23 

+ 143 

H 

1500 

+ 16 

-16 

0 

1200 

+ 6 

' - 6 

0 

3881 

+ 64 

- 16 

+ 48 

5294 

+ 115 

- 32 

+ 83 

I 

1500 

+ 20 

-20 

0 

1200 

+ 8 

- 8 

0 

3885 

+ 60 

- 40 

+ 20 

5600 

+ 78 

- 40 

+ 38 

J 

1500 

0 

-16 

- 16 

1200 

0 

-16 

- 16 

4025 

+ 30 

- 46 

- 16 

6281 

+ 49 

- 68 

- 19 

K 

1500 

0 

-20 

- 20 

1200 

0 

-20 

- 20 

4150 

+ 18 

- 63 

- 45 

6415 

+ 42 

-108 

- 66 

L 

1483 

0 

-44 

- 44 

1105 

0 

-24 

- 24 

5215 

+ 12 

-121 

-109 

6346 

+ 33 

-153 

-120 

M 

1443 

0 

-82 

- 82 

1128 

0 

-63 

- 63 

6093 

+ 1 

-358 

-357 

5314 

+ 23 

-310 

-287 

N 

1359 

0 

-71 

- 71 

1156 

0 

-58 

- 58 

5375 

+ 9 

-284 

-275 

5950 

+ 17 

-317 

-300 

O 

1089 

0 

-61 

- 61 

1262 

0 

-69 

- 69 

4736 

+ 2 

-229 

-227 

5965 

0 

-287 

-287 

18 




— 9 




- 12 




- 46 




- 54 

17 




— 9 




- 12 




— 49 




- 53 

16 




— 9 




— 12 




— 51 




— 50 

15 




- 9 




— 12 




- 51 




— 61 

14 




— 9 




- 16 




- 46 




- 48 

13 




— 19 




— 25 




- 73 




- 78 

12 




— 13 




- 16 




- 43 




- 46 

11 




— 10 




- 15 




— 34 




- 32 

10 




— 8 




- 13 




- 20 




- 18 

9 




— 8 




- 7 




- 5 




- 2 

g 




4- 1 

* 



- 8 




+ 5 




+ 7 

7 




+ 5 




4- 5 




+ 6 




+ 6 

6 




4- 8 




+ 9 




+ 9 




+ 8 

5 




+ 9 




+ 10 




+ 9 




+ 8 

4 




4- 6 




+ 6 




+ 7 




+ 7 

3 




+ 4 




+ 4 




+ 4 




+ 4 

o 




+ A 




+ 4 




+ s 




+ 3 

1 




+ i 








+ 1 




+ 1 





















+ 100 




+ 9 




-306 




- 73 




































































































































































































































32 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Skyomish, Wash., No. Ill 

Olympia, Wash., No. 112 

Heppner, Oreg., No. 113 

Truckee, Cal., No. 114 

A 

920 

+ 2 

0 

-f 2 

62 

+ 2 

0 

+ 2 

1960 

+ 2 

0 

+ 2 

5922 

■f* 2 

0 

+ 2 

B 

920 

+04 

0 

+ 64 

60 

+ 16 

0 

+ 16 

1960 

+ 68 

0 

+ 68 

5920 

+ 68 

0 

+ 68 

C 

920 

+96 

0 

+ 96 

60 

+ 4 

0 

+ 4 

1960 

+ 136 

0 

+ 136 

5925 

+ 163 

- 4 

+ 159 

D 

933 

+ 72 

0 

+ 72 

60 

0 

0 

0 

1960 

+ 180 

0 

+ 180 

5940 

+308 

- 6 

+302 

E 

1144 

+28 

0 

+ 28 

60 

0 

0 

0 

1960 

+ 134 

- 6 

+ 128 

6019 

+420 

- 16 

+404 

F 

1740 

+ 3 

- 5 

- 2 

60 

0 

0 

0 

1960 

+ 69 

- 9 

+ 60 

6070 

+344 

- 20 

+324 

G 

1925 

- 5 

- 6 

- 11 

60 

0 

0 

0 

1960 

+ 35 

- 11 

+ 24 

6142 

+211 

- 24 

+ 187 

H 

2275 

- 1 

- 13 

- 14 

60 

0 

0 

0 

1960 

+ 32 

- 16 

+ 16 

6150 

+ 151 

- 32 

+ 119 

I 

2885 

-19 

- 27 

- 46 

60 

0 

0 

0 

1960 

+ 20 

- 20 

0 

6335 

+ 123 

- 51 

+ 72 

J 

3575 

- 6 

- 40 

- 46 

60 

0 

0 

0 

1960 

0 

- 16 

- 16 

6756 

+ 64 

- 75 

- 11 

IC 

3625 

-22 

- 52 

- 74 

75 

0 

0 

0 

1960 

0 

- 20 

- 20 

7005 

+ 62 

-120 

- 58 

L 

3283 

- 9 

- 79 

- 88 

88 

0 

0 

0 

1475 

0 

- 36 

- 36 

6912 

+ 38 

-163 

-125 

M 

2678 

- 4 

-158 

-162 

309 

0 

-17 

- 17 

2286 

0 

-133 

-133 

5857 

+ 33 

-342 

-309 

N 

2081 

+ 2 

-109 

-107 

1206 

0 

-62 

- 62 

2644 

0 

-133 

-133 

4875 

+ 8 

-254 

-246 

0 

1775 

- 1 

- 90 

- 91 

1174 

0 

-58 

- 58 

3021 

0 

-151 

-151 

3661 

+ 1 

-183 

-182 

18 




— 17 




- 6 




- 35 




- 38 

17 




— 16 




- 6 




— 33 




- 37 

16 




— 16 




- 5 




- 31 




— 40 

15 




— 15 




— 4 




- 27 




- 43 

14 




- 16 




— 6 




- 32 




- 37 

13 




— 29 




- 13 




- 49 




- 23 

12 




- 21 




- 11 




— 23 




+ 2 

11 




- 10 




- 3 




- 16 




+ 10 

10 




— 1 




4 3 




0 




+ 8 

9 




+ 3 




+ 5 




+ 6 




+ 8 

8 




+ 9 




+ 10 




+ 10 




+ 13 

7 




+ 6 




+ 6 




+ 7 




+ 9 

6 




+ 7 




+ 7 




+ 7 




+ 8 

5 




+ 8 




+ 8 




+ 8 




+ 9 

4 




+ 7 




+ 7 




+ 7 




+ 8 

3 




+ 3 




4 3 




+ 3 




+ 4 

2 




+ 3 




4 3 




+ 3 




+ 4 

1 




+ / 




+ i 




+ i 




+ i 







• 









Total.. 




-473 




-116 




- 69 




+572 


















Winnemucca, 

Nev., No. 115 

Ely, Nev., No. 116 

Guernsey, Wyo., No 117 

Pierre, S. Dak., No. 118 

A 

4300 

4* 2 

0 

+ 2 

6435 

4 2 

0 

+ 2 

4336 

+ 2 

0 

+ 2 

1490 

+ 2 

0 

+ 2 

B 

4300 

+ 68 

0 

+ 68 

6435 

+ 68 

0 

+ 68 

4340 

+ 68 

0 

+ 68 

1490 

+ 64 

0 

+ 64 

C 

4300 

+ 159 

- 3 

+ 156 

6437 

+ 164 

- 4 

+ 160 

4340 

+ 157 

- 1 

+ 156 

1490 

+ 124 

0 

+ 124 

D 

4300 

+282 

- 6 

+276 

6487 

+314 

- 6 

+308 

4355 

+282 

- 6 

+276 

1490 

+ 138 

0 

+ 138 

E 

4300 

+328 

- 8 

+320 

6625 

+440 

- 16 

+424 

4384 

+331 

- 8 

+323 

1490 

+ 80 

0 

+ 80 

F 

4300 

+230 

- 10 

+220 

6800 

+381 

- 20 

+361 

4423 

+225 

- 10 

+215 

1490 

+ 30 

0 

+ 30 

G 

4300 

+ 120 

- 12 

+ 108 

6875 

+237 

- 24 

+213 

4519 

+ 121 

- 13 

+ 108 

1490 

+ 12 

0 

+ 12 

H 

4600 

+ 83 

- 21 

+ 62 

6835 

+ 170 

- 32 

+ 138 

4541 

+ 79 

- 18 

+ 61 

1490 

+ 16 

- 16 

0 

I 

4425 

+ 76 

- 40 

+ 36 

6930 

+ 142 

- 60 

+ 82 

4616 

+ 67 

- 40 

+ 27 

1490 

+ 20 

- 20 

0 

J 

4408 

+ 35 

- 48 

- 13 

7237 

+ 73 

- 79 

- 6 

4694 

+ 40 

- 48 

- 8 

1498 

0 

- 16 

- 16 

K 

4445 

+ 29 

- 69 

- 40 

7745 

+ 74 

-138 

- 64 

4750 

+ 31 

- 72 

- 41 

1597 

0 

- 20 

- 20 

L 

4508 

+ 28 

-107 

- 79 

7446 

+ 33 

-170 

-137 

4839 

0 

- 96 

- 96 

1703 

0 

- 41 

- 41 

M 

5000 

+ 14 

-294 

-280 

6850 

+ 37 

-396 

-359 

5114 

+ 12 

-305 

-293 

1771 

0 

-101 

-101 

N 

5156 

+ 14 

-279 

-265 

6531 

+ 20 

-346 

-326 

5400 

+ 11 

-288 

-277 

1956 

0 

- 95 

- 95 

0 

5043 

0 

-275 

-275 

6196 

0 

-301 

-301 

5475 

0 

-268 

-268 

2107 

0 

-108 

-108 

18 




- 55 




- 59 




- 54 




- 22 

17 




— 54 




- 57 




- 55 




- 22 

16 




- 57 




- 57 




- 56 




— 23 

15 




- 56 




- 56 




- 54 




— 26 

14 




- 54 




- 51 




— 52 




— 26 

13 




- 77 




- 79 




- 84 




— 42 

12 




- 32 




- 39 




— 48 




— 27 

11 




- 8 




- 17 




- 33 




— 26 

10 




4* 3 




- 2 




- 22 




— 17 

9 




+ 4 




0 




- 6 




— 8 

8 




+ u 




+ 11 




+ 5 




— 3 

7 




+ 8 




+ 9 




+ 7 




+ 6 

6 




+ 8 




+ 9 




+ 9 




4 . 9 

5 




+ 9 




+ 9 




+ 10 




+ u 

4 




+ 8 




+ 8 




+ 8 




+ 7 

3 




+ 4 




+ 5 




+ 5 




+ 4 

2 




+ 4 




+ 4 




+ 3 




-j- 3 

1 




+ 1 




+ i 




+ 1 




-f 1 


















Total.. 




- 37 




+202 




—163 




-132 





































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


33 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Corn- 

pens 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Fort Dodge, Iowa, No. 119 

Keithsburg, 

m., No. 

120 

Grand Rapids, 

Mich., No. 121 

Angola, Ind., No. 122 

A 

1116 

4- 2 

0 

4- 2 

547 

4- 2 

0 

+ 2 

774 

+ 2 

0 

+ 2 

1043 

2 

0 

4- 2 

B 

1116 

+ 64 

0 

+ 64 

547 

+56 

0 

+56 

774 

+60 

0 

+ 60 

1013 

+ 64 

0 

+ 64 

C 

1116 

+ 108 

0 

+ 108 

550 

+ 64 

0 

+ 64 

774 

+84 

0 

+84 

1043 

+ 104 

0 

+ 104 

D 

1116 

+ 96 

0 

+ 96 

550 

+36 

0 

+36 

774 

+ 54 

0 

+ 54 

1040 

+ 90 

0 

+ 90 

E 

1116 

+ 48 

0 

+ 48 

550 

+ 16 

0 

+ 16 

774 

+ 24 

0 

+ 24 

1040 

+ 40 

0 

+ 40 

F 

1116 

+ 20 

0 

+ 20 

550 

0 

0 

0 

774 

+ 10 

0 

+10 

1040 

+ 20 

0 

+ 20 

G 

1116 

0 

0 

0 

550 

0 

0 

0 

774 

0 

0 

0 

1000 

0 

0 

0 

H 

1116 

+ 4 

- 4 

0 

550 

0 

0 

0 

774 

0 

0 

0 

1000 

0 

0 

0 

I 

1116 

+ 5 

- 5 

0 

550 

0 

0 

0 

730 

0 

0 

0 

1000 

0 

0 

0 

J 

1116 

0 

-16 

- 16 

550 

0 

-16 

-16 

737 

0 

-16 

-16 

1000 

0 

-16 

- 16 

K 

1116 

0 

-20 

- 20 

550 

0 

-20 

-20 

737 

0 

-20 

-20 

1000 

0 

-20 

- 20 

L 

1110 

0 

-24 

- 24 

550 

0 

-24 

-24 

690 

0 

-24 

-24 

971 

0 

-24 

- 24 

M 

1150 

0 

-63 

- 63 

614 

0 

-33 

-33 

683 

0 

-37 

-37 

902 

0 

-53 

- 53 

N 

1103 

0 

-54 

- 54 

662 

0 

-32 

-32 

711 

0 

-39 

-39 

744 

0 

-36 

- 36 

O 

1139 

0 

-61 

- 61 

686 

0 

-38 

-38 

713 

0 

-44 

-44 

737 

0 

-41 

- 41 

18 




— 11 




— 7 




- 7 




- 7 

17 




— 11 




- 7 




- 7 




- 7 

16 




~ 11 




- 7 




- 7 




- 7 

15 




— 12 




- 7 




- 8 




- 8 

14 




— 13 




— 9 




- 9 




- 9 

13 




— 22 




— 18 




-16 




- 16 

12 




— 15 




— 11 




-10 




- 9 

H 




— 1A 




- 8 




- 4 




- 4 

10 




— 11 




- 6 




- l 




+ 1 

9 




— 6 




— 2 




+ 1 




+ 2 

g 




0 




+ 3 




+ 6 




+ 6 

7 




+ 7 




+ 7 




+ 7 




+ 7 

Q 




4- 9 




+ 8 




+ 8 




+ 8 

5 




4 - 10 




+ 10 




+ 8 




+ 8 

4 




4- 6 




+ 7 




+ 6 




+ 6 

9 




4- A 




+ 5 




+ 5 




+ 6 

2 




4- A 




+ 3 




+ 4 




+ 4 

l 




+ i 




+ 1 




+ 1 




+ 1 




















+ 15 




-27 




+31 




+ 111 


















Total. 


Albany, N. Y., No. 123 


A 

200 

+ 2 

0 

4- 2 

461 

4- 2 

0 

B 

200 

+40 

0 

+40 

461 

+56 

0 

C 

185 

+ 13 

0 

+ 13 

460 

+52 

0 

D 

183 

+ 6 

0 

+ 6 

451 

+23 

0 

E 

172 

+ 7 

0 

+ 7 

465 

+ 9 

0 

F 

155 

0 

0 

0 

568 

+ 4 

0 

G 

155 

0 

0 

0 

727 

0 

0 

H 

196 

0 

0 

0 

919 

0 

0 

I 

257 

0 

0 

0 

948 

- 6 

- 3 

J 

306 

0 

- 2 

- 2 

956 

0 

-15 

K 

393 

0 

- 7 

- 7 

830 

0 

-18 

L 

671 

0 

-15 

-15 

883 

0 

-27 

M 

922 

0 

-54 

-54 

1007 

0 

-58 

N 

1215 

0 

-63 

-63 

888 

0 

-49 

O 

1071 

0 

-57 

-57 

713 

0 

-38 

18 




- 8 




17 




- 8 




16 




- 8 

... 



15 




- 5 

. 



11 




- 4 




1 ? 




+ i 




19 




+n 




11 




+ 15 




10 




+/4 




9 




+ 10 




9 




+U 




7 




+ 6 








+ 6 








+ 6 








+ 6 




9 




+ 6 




9 




+ ^ 




l 




+ / 








-60 













Port Jervis, N. Y., No. 124 


+ 2 
+56 
+52 
+23 
+ 9 

+ 4 
0 
0 

- 9 
—15 

-18 

-27 

-58 

-49 

-38 

- 7 

- 7 

- 4 

- 2 
0 

+ 7 
+ 17 
+17 

+ U 

+ 10 

+ U 
+ 6 
+ 6 
+ 6 
+ 6 

+ 6 
+ 4 
+ 1 


+ 26 


Atlantic City, N. J., No. 125 


Bridgehampton, N. Y., No. 126 


12 

+ 2 

0 

+ 2 

32 

+ 2 

0 

+ 2 

14 

+ 2 

0 

+ 2 

32 

+ 8 

0 

+ 8 

14 

0 

0 

0 

32 

0 

0 

0 

7 

0 

0 

0 

35 

0 

0 

0 

0 

0 

0 

0 

42 

0 

0 

0 

- 4 

0 

0 

0 

42 

0 

0 

0 

- 6 

0 

0 

0 

52 

0 

0 

0 

- 8 

0 

0 

0 

66 

0 

0 

0 

-10 

0 

0 

0 

22 

0 

0 

0 

- 9 

0 

0 

0 

- 8 

0 

0 

0 

- 2 

0 

0 

0 

-16 

0 

0 

0 

- 9 

0 

0 

0 

-31 

0 

+1 

+ 1 

+ 4 

0 

0 

0 

-54 

0 

4-3 

+ 3 

-21 

0 

0 

0 

4 

0 

0 

0 

+ 15 

0 

0 

0 

75 

0 

-1 

- 1 




+ 1 




+ 1 




+ 4 




+ 5 




+ 10 




+ 8 




+ 12 




+ 7 




+ 14 




+ 8 




+ 21 




+ 24 




+ 19 




+ 22 




+ 20 




+ 25 




+ 18 




+ 20 




+ 12 




+ IS 




+ 15 




+ 17 




+ 6 




+ 6 




+ 6 




+ 6 




+ 6 




+ 6 




+ 6 




+ 6 




+ 6 




+ 6 




+ 4 




+ 4 




+ i 




+ 1 











+ 185 




+ 198 









59387°—17-3 







































































































































































































































34 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


Mean elevations and corrections for topography and isostatic compensation , separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Chatham, Mass., No. 127 

Rockland, Me., No. 128 

Lancaster, N. H., No. 129 

Whitehall, N. Y., No 

. 130 

A 

5 

+ 1 

0 

+ 1 

31 

+2 

0 

+ 2 

856 

+ 2 

0 

+ 2 

125 

+ 2 

0 

+ 2 

B 

10 

+2 

0 

+ 2 

32 

+ 8 

0 

+ 8 

858 

+60 

0 

+60 

125 

+28 

0 

+ 28 

C 

19 

0 

0 

0 

30 

0 

0 

0 

851 

+90 

0 

+90 

129 

+ 8 

0 

+ 8 

D 

20 

0 

0 

0 

34 

0 

0 

0 

870 

+68 

0 

+68 

167 

+ 4 

0 

+ 4 

E 

10 

0 

0 

0 

42 

0 

0 

0 

896 

+32 

- 2 

+30 

200 

+ 2 

0 

+ 2 

F 

4 

0 

0 

0 

51 

0 

0 

0 

920 

+ 12 

- 3 

+ 9 

224 

0 

0 

0 

G 

5 

0 

0 

0 

90 

0 

0 

0 

1021 

+ 4 

- 4 

0 

298 

0 

0 

0 

H 

- 5 

0 

0 

0 

92 

0 

0 

0 

1081 

+ 2 

- 5 

- 3 

325 

0 

0 

0 

I 

- 10 

0 

0 

0 

51 

0 

0 

0 

1088 

+ 10 

-10 

0 

518 

0 

0 

0 

.T 

- 6 

0 

0 

0 

63 

0 

0 

0 

1231 

+ 2 

-13 

-11 

666 

0 

- 8 

- 8 

K 

- 27 

0 

0 

0 

71 

0 

-1 

- 1 

1470 

+ 2 

-24 

-22 

642 

0 

-12 

- 12 

L 

- 48 

0 

+1 

+ 1 

1 

0 

0 

0 

1421 

0 

-33 

-33 

823 

0 

-19 

- 19 

M 

- 89 

0 

+4 

+ 4 

- 15 

0 

0 

0 

1557 

0 

-87 

-87 

1071 

0 

-60 

- 60 

N 

-159 

0 

+9 

+ -L 

- 38 

0 

+2 

+ 2 

962 

0 

-52 

-52 

1088 

0 

-58 

- 58 

0 

-126 


+ 7 

+ 7 

165 

0 

-8 

- 8 

704 

0 

-38 

-38 

1071 

0 

-58 

- 58 

18 




0 




— 3 




- 5 




— 9 

17 




+ 1 




- 4 




- 5 




— 8 

16 




+ 5 




— 3 








— 6 

15 




+ 10 




- 3 




- 5 




— 6 

14 




+ 16 




- 3 








— 5 

13 




+ 37 




+ 2 




- 8 




— 5 

12 




+ 33 




+ 15 




+ 3 




4- 7 

11 




+ 27 




+ 20 




+ 10 




4- 11 

10 




+ 21 




+ 18 




4 -U 




4- 18 

9 




+ 13 




+ 13 




+u 




4- in 

8 




+ 18 




+ 16 




+ 13 




4- 1.8 

7 




+ 8 




+ 6 




-f 6 




4- 8 

6 




+ 6 




+ 6 




+ 6 




4- ft 

5 




+ G 




+ 5 




4- 6 




4- 8 

4 




+ 6 




+ 6 




4- 6 




4- 8 

3 




+ 6 




+ o 




-f 6 




4- 8 

2 




+ 4 




+ 5 




+ 5 




4- / 

1 




+ 1 




+ 1 

. 



+ 1 




• * 
+ / 

Total... 




+240 




+ 106 




+68 




-121 










. 

. 






Little Falls, N. Y., No. 131 

Watertown, N. Y., No. 132 

Southport, N. Y., No. 133 

Erie, Pa. 

No. 134 


A 

448 

+ 2 

0 

+ 2 , 

483 

+ 2 

0 

+ 2 

873 

+ 2 

0 


650 

+ 2 

0 

+ 2 

B 

444 

+56 

0 

+56 

489 

+56 

0 

+56 

875 

+60 

0 

+ 60 

650 

+58 

0 

+58 

c 

450 

+53 

0 

+53 

488 

+58 

0 

+58 

875 

+94 

O 

+94 

650 

+76 

0 

+76 

D 

525 

+24 

0 

+24 

475 

+29 

0 

+29 

875 

+69 

0 

+69 

648 

+48 

0 

+48 

E 

662 

+ 7 

0 

+ 7 

4/o 

+ 8 

0 

+ 8 

894 

+32 

0 

+32 

640 

+ 16 

0 

+16 

F 

770 

+ 2 

- 1 

+ 1 

470 

+ 2 

0 

+ 2 

996 

+18 

- 4 

+14 

643 

+ 10 

0 

+ 10 

G 

796 

0 

— 2 

- 2 

481 

0 

0 

0 

1038 

+ 5 

- 5 

0 

666 

0 

0 

o 

H 

7<5 

+ 3 

- 4 

- 1 

536 

+ 2 

- 2 

0 

1136 

+ 5 

- 6 

- 1 

700 

4- 7 


o 

I 

842 

+ 2 

— 8 

- 6 

600 

+ 7 

- 7 

0 

1340 

+ 7 

-14 

- 7 

752 

+ 9 

- 9 

o 

J 

944 

0 

-10 

-10 

619 

0 

- 7 

— 7 

1362 

0 

-16 

-16 

782 

0 

- 8 

- 8 

K 

1102 

0 

-16 

-16 

670 

0 

-10 

-10 

1355 

0 

-20 

-20 

776 

0 

-13 

—13 

I. 

1254 

0 

-31 

-31 

665 

0 

-13 

-13 

1429 

0 

-34 

-34 

746 

0 

-18 

—18 

M 

1179 

0 

-66 

—66 

714 

0 

-42 

-42 

1207 

0 

-68 

-68 

800 

0 

—44 

—44 

N 

1188 

0 

-62 

-62 

706 

0 

-38 

-38 

1244 

0 

—65 

-65 

875 

0 

—47 

—47 

0 

1050 

0 

-58 

-58 

786 

0 

-49 

-49 

1104 

0 

-60 

-60 

861 

0 

-51 

-51 

18 




-10 




- 8 




9 





17 




-10 




- 7 




— 8 





16 




- 7 


. 


- 9 




g 





15 




- 6 



- 8 




7 




— 9 

14 




- 8 



- 8 




— 7 





13 




- 5 



-13 




5 





12 




+ 8 



- 1 




4- 7 





11 




+ 9 

. 


+ 2 




4- 8 




- 2 

10 




+ 12 



+ 8 




4- 11 




9 




+ 9 



+ 7 




4- R 




4- o 

8 




+13 



+ 11 




4 -19 




4- O 

7 




+ 6 




+ 7 




4 - 8 




4- 0 

6 




+ 6 




+ 6 




4 - 8 




4- o 

5 




+ 7 


. 


+ 6 




4- 7 




4- 7 

4 




+ G 




+ 5 




4- 8 




4- 7 

3 




+ 6 




+ 6 




4- 8 




4- 6 

2 




+ 4 




+ 5 




4- /. 




4- o 

1 




+ l 




+ 1 




• 4 
4- 1 




+ 4 
+ 1 

Total... 




-66 


. 


+ 6 




+38 



+11 








































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 35 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations— Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Parkersburg,W.Va., No. 135 

Columbus, Ohio, No. 136 

Indianapolis, Ind., No. 137 

Springfield, Ill., No. 

138 

A 

606 

-f 2 

0 

+ 2 

760 

+ 2 

0 

+ 2 

713 

+ 2 

0 

+ 2 

600 

+ 2 

0 

+ 2 

B 

615 

+56 

0 

+56 

760 

+60 

0 

+60 

710 

+60 

0 

+ 60 

600 

+56 

0 

+56 

C 

618 

+72 

0 

+72 

755 

+84 

0 

+84 

710 

+80 

0 

+80 

600 

+ 72 

0 

+72 

D 

612 

+42 

0 

+42 

757 

+55 

0 

+55 

710 

+48 

0 

+48 

600 

+ 42 

0 

+42 

E 

631 

+ 16 

0 

+ 16 

752 

+24 

0 

+24 

700 

+20 

0 

+20 

595 

+ 20 

0 

+20 

F 

622 

+ 1 

0 

+ 1 

758 

+ 10 

0 

+10 

700 

+ 12 

- 2 

+10 

594 

+ 5 

0 

+ 5 

G 

665 

0 

0 

0 

750 

+ 2 

- 2 

0 

700 

+ 3 

- 3 

0 

595 

0 

0 

0 

n 

709 

+ 3 

- 3 

0 

761 

+ 3 

- 3 

0 

750 

+ 3 

- 3 

0 

593 

+ 3 

- 3 

0 

i 

742 

+ 8 

- 8 

0 

780 

+ 8 

- 8 

0 

750 

+ 10 

-10 

0 

592 

+ 5 

- 5 

0 

j 

719 

0 

-16 

-16 

802 

0 

-11 

-11 

800 

0 

- 8 

- 8 

593 

0 

- 8 

- 8 

K 

775 

0 

-20 

-20 

838 

0 

-15 

-15 

800 

0 

-10 

-10 

596 

0 

-10 

-10 

L 

800 

0 

-24 

-24 

890 

0 

-24 

-24 

800 

0 

-24 

-24 

600 

0 

-12 

-12 

M 

921 

0 

-52 

-52 

950 

0 

-56 

-56 

850 

0 

-50 

-50 

579 

0 

-28 

-28 

N 

1000 

0 

-51 

-51 

994 

0 

-48 

-48 

794 

0 

-41 

-41 

581 

0 

-32 

-32 

0 

1221 

0 

-68 

-68 

879 

0 

-56 

-56 

675 

0 

-34 

-34 

568 

0 

-30 

-30 

18 




-14 




- 8 




- 7 




6 

17 




-14 




— 9 




— 7 




— 6 

16 




-IS 




—10 




— 7 




6 

15 




-12 




— g 




— 7 




7 

14 




-10 




— 9 




— 7 




8 

13 




-IS 




-15 




— 16 




—17 

12 




- 4 




— 8 




— 9 




10 

11 




+ 5 




— 3 




— 6 




8 

10 




+ 8 




+ 5 




0 




& 

9 




+ 7 




+ 5 




-f 2 




— 1 

8 




+ 8 




+ 7 




+ 5 




+ 3 

7 




+ 6 




+ 6 




+ 7 




4- 7 

6 




+ 6 




+ 7 




+ 8 




+ 8 

5 




+ 8 




+ 9 




+ 9 

r 


+10 

4 




+ 7 




+ 7 




+ 7 




+ 7 

3 




+ 6 




+ 6 




+ 6 




+ 6 

2 




+ S 




-f- s 




+ 3 




4- 3 

1 




+ 1 




+ 1 




+ 1 




+ 1 





















-58 




+ 9 




+34 




+47 
















Lebanon, Mo., No. 139 

Joplin, Mo., No. 140 

Fort Smith, 

Vrk., No. 141 

Texarkana, Ark., No 

142 

A 

1263 

+ 2 

0 

+ 2 

994 

+ 2 

0 

+ 2 

442 

+ 2 

0 

+ 2 

325 

-f 2 

0 

+ 2 

B 

1260 

+ 64 

0 

+ 64 

995 

+ 64 

0 

+ 64 

450 

+56 

0 

+56 

325 

-f 48 

0 

+48 

C 

1261 

+ 116 

0 

+ 116 

995 

+ 104 

0 

+ 104 

450 

+52 

0 

+52 

325 

+36 

0 

+36 

D 

1260 

+ 114 

0 

+ 114 

992 

+ 84 

0 

+ 84 

450 

+ 24 

0 

+ 24 

318 

+ 14 

0 

+ 14 

E 

1225 

+ 70 

- 4 

+ 66 

988 

+ 43 

- 3 

+ 40 

450 

+ 8 

0 

+ 8 

310 

+ 8 

0 

+ 8 

F 

1230 

+ 31 

- 5 

+ 26 

1002 

+ 19 

- 3 

+ 16 

465 

0 

0 

0 

308 

0 

0 

0 

G 

1233 

+ 10 

- 6 

+ 4 

988 

+ 4 

- 4 

0 

479 

0 

0 

0 

316 

0 

0 

0 

H 

1206 

+ 6 

- 6 

0 

997 

+ 5 

- 5 

0 

462 

0 

0 

0 

316 

0 

0 

0 

I 

1145 

+ 10 

-10 

0 

992 

+ 10 

-10 

0 

459 

+ 5 

- 5 

0 

310 

0 

0 

0 

J 

1131 

+ 3 

-12 

- 9 

972 

0 

-16 

- 16 

512 

+ 4 

- 8 

- 4 

300 

0 

0 

0 

K 

1145 

0 

-20 

- 20 

955 

0 

-20 

- 20 

552 

0 

- 7 

- 7 

285 

0 

- 6 

- 6 

L 

1096 

0 

-24 

- 24 

1000 

0 

-24 

- 24 

623 

0 

-14 

-14 

367 

0 

- 8 

- 8 

M 

1129 

0 

-63 

- 63 

1029 

0 

-57 

- 57 

871 

0 

-50 

-50 

351 

0 

-21 

-21 

N 

1131 

0 

-55 

- 55 

1038 

0 

-54 

- 54 

1006 

0 

-52 

-52 

406 

0 

-28 

-28 

0 

1032 

0 

-57 

- 57 

1032 

0 

-62 

- 62 

911 

0 

-47 

-47 

512 

0 

-33 

-33 

1 ft 




— 9 




- 12 




- 8 




- 5 

17 




— 9 




— 11 




- 7 




— 5 

ifi 




— 9 




— 11 




- 7 




— 5 

is 




— 7 




— 10 




- 8 




- 5 

14 




7 




- 10 




- 8 




- 6 





— 17 




- 17 




-14 




- 8 

19 




— 11 




- 12 




-11 




- 5 

11 




— 11 




- 13 




-10 




- 6 

in 




— 8 




- 11 




- 8 




- 6 

9 




- 4 



. 

- 5 




- 4 




- 3 

& 




+ 1 




"f 1 




+ 2 




+ 3 





+ 8 




+ 8 




+ 8 




+ 8 

A 




+ 9 




+ 9 




+ 9 




+ 9 

5 




+ a 




+ 11 




+11 




+11 

4 




+ 8 




+ 7 




+ 8 




+ 8 

0 




+ 5 




+ 5 




+ 5 




+ 5 

2 




+ 3 




+ 3 




+ 3 




+ 3 

i 




+ / 




+ 1 




+ / 




+ 1 





















+ 118 




+ 10 




-70 




+ 7 












































































































































































































































36 u. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Mean elevations and corrections for topography and isostatic compensation,separate zones, for United States stations —Contd 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Hot Springs, Ark., No. 143 

Alexandria, 

La., No. 

144 

Laurel, Miss., No. 145 

Richmond, Va., No. 

146 

A 

620 

+ 2 

0 

4- 2 

76 

+ 2 

0 

4~ 2 

250 

+ 2 

0 

+ 

2 

97 

4* 2 

0 

4- 2 

B 

620 

+56 

0 

+56 

76 

+20 

0 

+20 

250 

+44 

0 

+ 

44 

100 

+24 

0 

+24 

C 

620 

+ 72 

0 

+72 

76 

+ 4 

0 

+ 4 

250 

+24 

0 

+ 

24 

85 

4- 4 

0 

+ 4 

D 

640 

+40 

0 

+ 40 

76 

+ 2 

0 

+ 2 

250 

+ 9 

0 

+ 

9 

93 

+ 2 

0 

+ 2 

E 

678 

+17 

0 

+ 17 

76 

0 

0 

0 

250 

+ 2 

0 

+ 

2 

90 

0 

0 

0 

F 

665 

+10 

0 

+ 10 

76 

0 

0 

0 

250 

0 

0 


0 

100 

0 

0 

0 

G 

658 

+ 2 

- 2 

0 

100 

0 

0 

0 

250 

0 

0 


0 

134 

0 

0 

0 

H 

601 

+ 3 

- 3 

0 

100 

0 

0 

0 

250 

0 

- 1 

— 

1 

144 

0 

0 

0 

I 

604 

0 

- 6 

- 6 

100 

0 

0 

0 

250 

0 

- 2 

— 

2 

152 

0 

0 

0 

J 

609 

0 

- 5 

- 5 

100 

0 

0 

0 

250 

0 

- 3 

— 

3 

156 

0 

0 

0 

K 

658 

0 

-14 

-14 

100 

0 

0 

0 

300 

0 

- 5 

_ 

5 

168 

0 

0 

0 

L 

604 

0 

-11 

-11 

100 

0 

0 

0 

300 

0 

- 7 

— 

7 

156 

0 

0 

0 

M 

607 

0 

-34 

-34 

64 

0 

0 

0 

250 

0 

-14 

— 

14 

158 

0 

- 8 

- 8 

N 

562 

0 

-33 

-33 

75 

0 

0 

0 

172 

0 

- 9 

— 

9 

187 

0 

-12 

-12 

0 

632 

0 

-35 

-35 

89 

0 

0 

0 

147 

0 

- 5 

— 

5 

314 

0 

-16 

-16 

18 




— 6 




- 1 





1 




- 5 

17 




- 6 




- 1 




_ 

1 




- 6 

16 




- 6 




- 1 





0 




- 7 

15 




- 6 




+ 1 




+ 

1 




- 7 

14 




— 6 




+ 2 




+ 

$ 




- 2 

13 




— 9 




+ 8 




+ 

9 




+ 13 

12 




- 7 




+ 8 




+ 

10 




+ 18 

11 




- 6 




+ 1 




+ 

5 




+ 18 

10 




- 4 




- 3 




+ 

4 




+18 

9 




- 6 



. 

- 1 




+ 

1 




+ 12 

8 




4- 2 




+ 5 




+ 

5 




+ 12 

7 




+ 8 




+ 8 




-f 

7 




+ 5 

6 




+ 9 




+ 10 




+ 

9 




+ 6 

5 




+ 11 




+ 10 





10 




+ 8 

4 




+ 7 




+ 8 




-f 

8 




+ 7 

3 




+ 5 




+ 6 




+ 

6 




+ 6 

2 




4- 3 




+ 2 




+ 

3 




+ 3 

1 




+1 




+ 1 




4- 

1 




+ 1 


















Total.. 




+44 




+ 91 




4-114 




+96 











1 







Emporia, Va., No. 147 

Greenville, N. C., No 

148 

Wilmington, N. C., No. 149 

Cheraw, S. 

C., No. 150 

A 

120 

4* 2 

0 

+ 2 

55 

+ 2 

0 

+ 2 

28 

+2 

0 

+ 

2 

180 

+ 2 

0 

+ 2 

B 

120 

+28 

0 

+ 28 

55 

+ 14 

0 

+ 14 

28 

+8 

0 

+ 

8 

180 

+36 

0 

+ 36 

C 

120 

+ 4 

0 

+ 4 

55 

+ 4 

0 

+ 4 


0 

0 


0 

180 

+ 12 

0 

+ 12 

D 

120 

+ 1 

0 

+ 1 

32 

0 

0 

0 


0 

0 


0 

ISO 

+ 6 

0 

+ 6 

E 

120 

0 

0 

0 

39 

0 

0 

0 


0 

0 


0 

180 

0 

0 

0 

F 

120 

0 

0 

0 

35 

0 

0 

0 


0 

0 


0 

200 

0 

0 

0 

G 

120 

0 

0 

0 

38 

0 

0 

0 


0 

0 


0 

200 

0 

0 

0 

H 

120 

0 

0 

0 

41 

0 

0 

0 


0 

0 


0 

200 

0 

0 

0 

I 

120 

0 

0 

0 

50 

0 

0 

0 


0 

0 


0 

300 

0 

0 

0 

J 

120 

0 

0 

0 

49 

0 

0 

0 


0 

0 


0 

300 

0 

0 

0 

K 

120 

0 

0 

0 

56 

0 

0 

0 


0 

0 


0 

300 

0 

0 

0 

L 

120 

0 

0 

0 

65 

0 

0 

0 


0 

0 


0 

300 

0 

0 

0 

M 

94 

0 

0 

0 

69 

0 

-4 

- 4 

- 5 

0 

0 


0 

286 

0 

-18 

- 18 

N 

149 

0 

-10 

- 10 

64 

0 

-3 

- 3 

15 

0 

0 


0 

291 

0 

-16 

- 16 

0 

212 

0 

-10 

- 10 

111 

0 

-5 

- 5 

-42 

0 

+4 

+ 

4 

315 

0 

-16 

- 16 

18 




- 3 




- 1 




4 - 

2 




— 4 

17 




- 4 




+ 1 




4 - 

4 




— 5 

16 




- 4 




+ 3 




4 - 

9 




— 5 

15 




+ 5 




+ 7 




4- 

13 




4- 2 

14 




+ 7 




+ 12 




4 - 

PI 




4- A 

13 




+ 15 




+ 34 




4 - 3A 




4 - 16 

12 




+ 20 




+ 24 




4 - 

29 




4 - 16 

11 




+ 21 




+ 22 




4 - 

28 




4 - 18 

10 




+ 17 




+ 19 




4 - 

20 




4- 18 

9 




+ 12 




+ 13 




4- 

IS 




4 - 12 

8 




+ 12 




+ IS 




4 - 

IS 




4 - 10 

7 




+ 5 




+ 6 




4 - 

6 




4- 6 

6 




+ 6 




+ 6 




4 - 

6 




4- 6 

5 




+ 8 




+ 8 




4- 

8 




4- 9 

4 




+ 7 




+ 7 




4- 

7 




4 - 7 

3 




+ 6 




+ 6 




4- 

6 




4- 6 

2 




+ 3 




4- 3 




4- 

3 




4- 3 

1 




+ 1 




+ i 




4 - 

i 




+ i 


















Total.. 




+ 149 




+ 191 




4-234 




+126 













































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 37 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Charlotte, N. C., No. 151 

Asheville, N. C., No. 152 

Cleveland, Tenn., No. 153 

Winston-Salem, N. C., No. 154 

A 

750 

4- 2 

0 

+ 2 j 

2199 

4- 2 

0 

+ 2 

864 

4* 2 

0 

+ 2 

932 

+ 2 

0 

+ 2 

B 

750 

+60 

0 

+ 60 

2200 

+ 68 

0 

+ 68 

864 

+60 

0 

+60 

932 

+64 

0 

+ 64 

C 

750 

+ 84 

0 

+ 84 

2200 

+ 140 

0 

+140 

864 

+94 

0 

+94 

932 

+98 

0 

+ 98 

D 

725 

+56 

0 

+ 56 

2200 

+ 196 

- 4 

+ 192 

864 

+ 70 

- 1 

+69 

900 

+78 

0 

+ 78 

E 

700 

+24 

0 

+ 24 

2200 

+156 

- 4 

+152 

870 

+30 

- 2 

+28 

900 

+39 

• - 2 

+ 37 

F 

705 

+12 

- 2 

+ 10 

2220 

+ 79 

- 5 

+ 74 

845 

+ 13 

- 3 

+10 

900 

+13 

- 3 

+ 10 

G 

707 

4- 2 

- 2 

0 

2225 

+ 41 

- 12 

+ 29 

872 

+ 3 

- 3 

0 

900 

+ 3 

- 3 

0 

H 

702 

+ 3 

- 3 

0 

2162 

+ 19 

- 16 

+ 3 

834 

+ 3 

- 3 

0 

900 

+ 3 

- 3 

0 

I 

701 

+ 6 

- 6 

0 

2265 

+ 20 

- 20 

0 

825 

+ 8 

- 8 

0 

900 

+ 8 

- 8 

0 

J 

697 

+ 1 

- 8 

- 7 

2312 

+ 5 

- 21 

- 16 

853 

0 

-16 

-16 

900 

0 

-16 

- 16 

K 

673 

0 

-11 

- 11 

2590 

+ 7 

- 42 

- 35 

828 

0 

-20 

-20 

900 

0 

-20 

- 20 

L 

688 

0 

-24 

- 24 

2871 

0 

- 68 

- 68 

850 

0 

-24 

-24 

900 

0 

-24 

- 24 

H 

595 

0 

-34 

- 34 

2657 

4~ 5 

-158 

-153 

1157 

0 

-67 

-67 

829 

0 

-16 

- 46 

N 

669 

0 

-38 

- 38 

1706 

0 

- 85 

- 85 

1394 

0 

-71 

-71 

925 

0 

-51 

- 51 

0 

904 

0 

-50 

— 50 

1415 

0 

- 74 

- 74 

1236 

0 

-65 

-65 

1146 

0 

-67 

- 67 

18 




- 9 




— 12 




—10 




— 10 

17 




- 9 




- 11 




—10 




— 10 

16 




- 9 




- 10 




- 9 




— 10 

15 




- S 




- 9 




— 7 




— 5 

14 




0 




— S 




- 5 




— 3 

13 




+ 7 




- 7 




- 7 




— 2 

12 




+ 11 




4- 2 




0 




-f 10 

11 




+ U 




+ 8 




+ 5 




+ U 

10 




+ 16 




+ u 




+ 10 




4- 17 

9 




+ 11 




+ 9 




+ 6 




+ a 

8 




+ 9 




+ 8 




+ 6 




+ 10 

7 




+ 6 




+ 6 




+ 6 




+ 5 

6 




+ 6 




+ 7 




+ 7 




+ 6 

5 




+ 9 




+ 10 




+ 10 




-f 9 

4 




+ 7 




+ 7 




+ 7 




+ 7 

3 




+ 6 




+ 6 




+ 6 




+ 6 

2 




+ 3 




+ 3 




+ 3 




+ 3 

1 




+ 1 




+ i 




+ 1 




+ i 
















Total . 




+ 148 




+256 




+19 




+124 

















Knoxville, Term., No. 155 

Bristol, Va., No. 156 

Homestead, 

Fla., No. 157 

Sebring, Fla., No. 158 

A 

919 

+ 2 

0 

+ 2 

1685 

+ 2 

0 

+ 2 

14 

+2 

0 

+ 2 

112 

+ 2 

0 

+ 2 

B 

919 

+64 

0 

+64 

1685 

+ 68 

0 

+ 68 

12 

0 

0 

0 

112 

+26 

0 

+ 26 

C 

920 

+96 

0 

+96 

1685 

+ 128 

0 

+128 

14 

0 

0 

0 

115 

+ 4 

0 

+ 4 

D 

920 

+ 78 

0 

+ 78 

1685 

+ 156 

0 

+ 156 

14 

0 

0 

0 

112 

0 

0 

0 

E 

900 

+38 

- 2 

+36 

1700 

+ 104 

- 4 

+100 

14 

0 

0 

0 

100 

0 

0 

0 

F 

890 

+15 

- 3 

+12 

1725 

+ 55 

- 5 

+ 50 

14 

0 

0 

0 

100 

0 

0 

0 

G 

875 

+ 6 

- 3 

*4* 3 

1779 

+ 30 

- 6 

+ 24 

14 

0 

0 

0 

100 

0 

0 

0 

II 

903 

+ 3 

- 3 

0 

1846 

+ 10 

- 10 

0 

14 

0 

0 

0 

100 

0 

0 

0 

I 

905 

+ 8 

- 8 

0 

1865 

+ 20 

- 20 

0 

14 

0 

0 

0 

100 

0 

0 

0 

J 

925 

0 

-16 

-16 

1825 

0 

- 16 

- 16 

14 

0 

0 

0 

100 

0 

0 

0 

K 

925 

0 

-20 

-20 

1840 

+ 3 

- 29 

- 26 

2 

0 

0 

0 

100 

0 

0 

0 

L 

1004 

0 

-24 

-24 

2100 

0 

- 51 

- 51 

3 

0 

0 

0 

100 

0 

0 

0 

M 

1400 

0 

-79 

-79 

2371 

+ 2 

-139 

-137 

- 77 

0 

4- 4 

4- 4 

83 

0 

-4 

- 4 

N 

1719 

0 

-88 

-88 

2125 

0 

-110 

-110 

-312 

0 

+19 

+ 19 

68 

0 

-4 

- 4 

0 

1550 

0 

-86 

-86 

1575 

0 

- 87 

- 87 

-439 

0 

+21 

+ 21 

11 

0 

0 

0 

18 




— 13 




- 14 




+ 5 




+ 1 

17 




— 12 




- 13 




+ 4 




4- 2 

16 




—ii 




- 12 




+ 4 




+ 4 

15 




- 8 




- 10 




+ 5 




+ 6 

14 




— 6 




- 6 




+ 9 




+ 9 

13 




— 9 




- 8 




+ 36 




+ 29 

12 




— 1 




+ 2 




+ 41 




+ 31 

ix 




+ 6 




+ 8 




+ 47 




+ 34 

in 




+ 11 




+ 13 




+ 27 




+ 23 

9 




+ 7 




+ 9 




+ 16 




+ 44 

g 




+ 6 




+ 8 




+ 16 




+ IS 

7 




+ 6 




+ 6 




+ 6 





g 




+ 7 




+ 7 




+ 6 




+ 6 





+ 10 




+ 10 




+ 10 




+ 10 

4 




+ 7 




+ 7 




+ 8 




+ 8 

3 




+ 6 




+ 6 




+ 6 





9 




+ $ 




+ 3 




+ 2 




+ 2 

i 




+ 1 




+ 1 




+ 1 




+ 1 


















TWol 




—13 




+118 




+292 




+228 





































































































































































































































38 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Titusville, Fla., No. 159 

Leesburg, Fla., No. 160 

Cedar Keys, Fla., No. 161 

Macon, Ga., No. 162 

A 

8 

+2 

0 

+ 2 

100 

+ 2 

0 

+ 

2 

8 

+2 

0 

4- 2 

326 

4- 2 

0 

+ 2 

B 

8 

0 

0 

0 

95 

+ 24 

0 

+ 

24 

8 

0 

0 

0 

332 

+50 

0 

+50 

C 

10 

0 

0 

0 

90 

+ 4 

0 


4 

4 

0 

0 

0 

326 

+36 

0 

+36 

D 

10 

0 

0 

0 

80 

+ 3 

0 

4- 

3 

4 

0 

0 

0 

300 

+ 15 

0 

+15 

E 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

300 

+ 4 

0 

+ 4 

F 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

300 

0 

0 

0 

G 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

300 

0 

- 1 

- 1 

H 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

350 

0 

- 2 

- 2 

I 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

350 

0 

- 3 

- 3 

J 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

400 

0 

- 4 

- 4 

K 

10 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

400 

0 

- 6 

- 6 

L 

15 

0 

0 

0 

80 

0 

0 


0 

2 

0 

0 

0 

400 

0 

-10 

-10 

M 

6 

0 

0 

0 

92 

0 

-4 

— 

4 

- 5 

0 

0 

0 

457 

0 

-26 

-26 

N 

- 35 

0 

0 

0 

59 

0 

-3 

— 

3 

9 

0 

0 

0 

481 

0 

-30 

-30 

0 

-302 

0 

+17 

+ 17 

18 

0 

0 


0 

22 

0 

0 

0 

525 

0 

-30 

-30 

18 




+ 4 





0 




o 




5 

17 




+ 5 




-f 

1 




o 




5 

16 




+ 5 




4- 

2 




o 




5 

15 




+ 5 




4- 

6 




4- 7 




3 

14 




+ 8 




4- 

8 




4- 




2 

13 




+ 26 




+ 24 




4 - 22 




4- 1 

12 




+ 30 




+ 26 




4- 20 




4 - ft 

11 




+ 34- 




+ 28 




4 - 20 




4 .11 

10 




+ H 




+ 21 




4- 1R 




4- 1ft 

9 




+ 14 




4- U 




4- 12 




_i_ m 

8 




+ 14 




+ 

12 




4- 7 / 




4 - ft 

7 




+ 6 




4- 

5 




4- ft 





6 




+ 6 




+ 

6 




4- 7 




4- 7 

5 




+ 10 





10 




4 - in 




4- in 

4 




+ 8 




-f- 

8 




4- 7 




4 - 7 

3 




+ 6 




-f 

6 




+ 6 





2 




4- 2 




4- 

2 



- 

4- 3 





1 




+ i 




+ 

1 




4 . 1 




+ i 

















Total.. 




+226 




4-206 




+ 163 




+67 


















Albany, Ga., No. 163 

Pensacola, Fla., No. 164 

Opelika, Ala., No. 165 

Huntsville, Ala., No. 166 

A 

190 

+ 2 

0 

-j- 2 

6 

4-1 

0 

+ 

1 

805 

+ 2 

0 

+ 2 

655 

+ 2 

0 

+ 2 

B 

200 

+40 

0 

+ 40 

11 

+2 

0 

+ 

2 

805 

+60 

0 

+ 60 

655 

+58 

0 

+58 

C 

200 

+16 

0 

+ 16 

11 

0 

0 


0 

800 

+88 

0 

+ 88 

655 

+76 

0 

+76 

D 

200 

+ 6 

0 

+ 6 

11 

0 

0 


0 

800 

+63 

0 

+ 63 

650 

+48 

0 

+48 

E 

200 

+ 1 

0 

+ 1 


0 

0 


0 

800 

+28 

0 

+ 28 

650 

+16 

0 

+16 

F 

200 

0 

0 

0 


0 

0 


0 

750 

+ 12 

- 2 

+ 10 

630 

+10 

0 

+10 

G 

200 

0 

0 

0 


0 

0 


0 

754 

+ 4 

- 3 

+ 1 

675 

0 

0 

0 

H 

200 

0 

- 1 

- 1 


0 

0 


0 

750 

+ 3 

- 3 

0 

772 

+ 3 

- 3 

0 

I 

250 

0 

— 2 

- 2 


0 

0 


0 

732 

+ 7 

- 8 

- 1 

762 

+ 8 

- 8 

0 

J 

250 

0 

— 3 

- 3 


0 

0 


0 

687 

0 

-16 

- 16 

738 

0 

-16 

-16 

K 

300 

0 

- 4 

- 4 


0 

0 


0 

650 

0 

-20 

- 20 

715 

0 

-20 

—20 

L 

300 

0 

— 7 

- 7 


0 

0 


0 

610 

0 

-16 

- 16 

742 

0 

—24 

—24 

M 

261 

0 

-13 

- 13 

21 

0 

0 


0 

557 

0 

-32 

- 32 

839 

0 

—47 

—47 

N 

208 

0 

-12 

- 12 

- 16 

0 

0 


0 

581 

0 

-31 

- 31 

812 

0 

—43 

—43 

o 

300 

0 

—15 

- 15 

-158 

0 

+9 

+ 

9 

532 

0 

-33 

- 33 

711 

0 

-40 

-40 

18 




- 2 




4- 

1 




5 





17 




- 3 




4- 

3 




5 





16 




- 3 




4- 

3 




4 




— i 

15 




+ 2 




4- 

6 




2 





14 




+ 4 




4- 

8 




n 





13 




+ 8 




4- 

16 








— 0 

12 




+ 8 




4- 

13 




a- / 




— O 

11 




+ 10 




4- 

8 




4- 7 




— o 

4- 2 

10 




+ 16 




4- 

9 




_L 19 




9 




+ 11 




4- 

5 




4- ft 




4- o 

8 




+ 9 




4- 

7 




4- 7 




4- o 

7 




+ 6 




4- 

7 




4- ft 




4- o 

6 




+ 7 




4- 

9 




4 - 7 




4- 6 

5 




+ 10 





10 




j- in 




4- 7 

4 




+ 7 




4- 

8 




4- 7 




4-10 

3 




+ 6 




4- 

6 








4- 7 

4- 6 

2 




+ 3 




4- 

3 








1 




+ 1 




4- 

1 




+ i 




4- 3 
4- 1 

Total.. 




+107 




4-1.25 




+167 





















4-34 


































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 39 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contcl. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Arkansas City 

, Ark., No. 167 

Memphis, Tenn., No 

. 168 

Mammoth Spring, Ark., 

No. 169 

Hopkinsville, Ky., No. 170 

A 

143 

+ 2 

0 

+ 2 

264 

+ 2 

0 

+ 2 

512 

+ 2 

0 

+ 2 

577 

+ 2 

0 

+ 2 

B 

143 

+ 32 

0 

+32 

264 

+44 

0 

+44 

512 

+56 

0 

+56 

577 

+56 

0 

+56 

C 

143 

+ 10 

0 

+ 10 

264 

+ 28 

0 

+ 28 

512 

+ 60 

0 

+ 60 

577 

+ 68 

0 

+68 

D 

134 

4- 3 

0 

+ 3 

264 

+ 6 

0 

+ 6 

512 

+30 

0 

+ 30 

600 

+ 36 

0 

+ 36 

E 

143 

0 

0 

0 

264 

+ 4 

0 

+ 4 

600 

+ 16 

0 

+ 16 

600 

+ 16 

0 

+ 16 

F 

143 

0 

0 

0 

264 

0 

0 

0 

600 

+ 5 

0 

+ 5 

600 

+ 5 

0 

+ 5 

G 

143 

0 

0 

0 

264 

0 

0 

0 

600 

0 

0 

0 

600 

0 

0 

0 

H 

143 

0 

0 

0 

264 

0 

0 

0 

700 

+ 3 

- 3 

0 

600 

+ 3 

- 3 

0 

I 

143 

0 

0 

0 

264 

0 

- 2 

- 2 

700 

+ 2 

- 6 

- 4 

600 

+ 2 

- 6 

- 4 

.1 

143 

0 

0 

0 

264 

0 

- 3 

- 3 

700 

0 

-11 

-11 

600 

0 

- 8 

- 8 

K 

143 

0 

0 

0 

264 

0 

- 4 

- 4 

700 

0 

-14 

-14 

600 

0 

-10 

-10 

L 

143 

0 

- 3 

- 3 

264 

0 

- 6 

- 6 

700 

0 

-17 

-17 

600 

0 

-12 

-12 

M 

129 

0 

- 7 

- 7 

307 

0 

-15 

-15 

679 

0 

-40 

-40 

500 

0 

-28 

-28 

N 

148 

0 

- 6 

- 6 

338 

0 

-20 

-20 

659 

0 

-38 

-38 

500 

0 

-32 

-32 

O 

141 

0 

- 7 

- 7 

341 

0 

-19 

-19 

711 

0 

-40 

-40 

529 

0 

-29 

-29 

18 




- 2 




— 4 




— 7 




— 6 

17 




- 3 




— 4 



_ 7 




— 6 

16 




- 3 




— 4 




— 6 




— 6 

15 




- 4 




— 5 




— 6 




— 7 

14 




- 4 




— 5 




— 6 




_ 7 

13 




- 2 




- 8 




—13 




—12 

12 




- l 




— 5 




— .9 




— 6 

11 




- l 




— 3 




_ 7 




_ 2 

10 




0 




+ 1 




— A 




+ 3 

9 




- 2 




_. i 




— 3 




4- 2 

8 




+ 3 




+ 8 




4- 2 




+ 4 

7 




+ s 




+ 7 




4- 7 




+ 7 

6 




+ 9 




+ 8 




+ 8 




+ 8 

5 




+ 11 




+10 




+10 




+ 10 

4 




+ 7 




-f 7 




4- 7 




+ 7 

3 




+ 5 




-f 6 




4 - 6 




+ 6 

2 




+ 3 




4- 3 




+ 3 




+ 3 

1 




+ 1 




+1 




+1 




+ 1 














Total 




+ 49 




+22 




-19 




+59 


















Danville, Ky., No. 171 

Clifton Forge 

Va., No. 172 

Greenville, Ala., No. 173 

Birmingham, 

Ala., No. 174 

A 

983 

+ 2 

0 

+ 2 

1066 

4- 2 

0 

+ 2 

427 

4- 2 

0 

+ 2 

586 

+ 2 

0 

+ 2 

B 

983 

+ 64 

0 

+ 64 

1066 

+ 64 

0 

+ 64 

427 

+56 

0 

+56 

590 

+56 

0 

+56 

C 

983 

+ 104 

0 

+ 104 

1066 

+ 108 

0 

+108 

400 

+52 

0 

+52 

590 

+72 

0 

+72 

D 

983 

+ 84 

0 

+ 84 

1066 

+ 90 

0 

+ 90 

400 

+20 

0 

+20 

590 

+42 

0 

+42 

E 

983 

+ 40 

0 

+ 40 

1212 

+ 49 

- 2 

+ 47 

400 

+ 8 

0 

+ 8 

600 

4”lto 

0 

+ 16 

F 

950 

+ 19 

- 3 

+ 16 

1320 

+ 23 

- 4 

+ 19 

400 

0 

- 1 

- 1 

624 

+ 5 

0 

+ 5 

G 

948 

+ 3 

- 3 

0 

1350 

+ 4 

- 5 

- 1 

400 

0 

- 1 

- 1 

671 

0 

0 

0 

H 

953 

+ 5 

- 5 

0 

1406 

+ 6 

- 8 

- 2 

300 

0 

- 2 

- 2 

666 

+ 3 

- 3 

0 

I 

940 

+ 10 

- 10 

0 

1515 

+ 6 

- 14 

- 8 

300 

0 

- 2 

- 2 

685 

+ 8 

- 8 

0 

J 

944 

0 

- 16 

- 16 

1850 

+ 4 

- 20 

- 16 

300 

0 

- 3 

- 3 

644 

0 

-15 

-15 

K 

940 

0 

- 20 

- 20 

1920 

+ 1 

- 31 

- 30 

300 

0 

- 4 

- 4 

640 

0 

-17 

-17 

L 

900 

0 

- 24 

- 24 

1946 

0 

- 45 

- 45 

300 

0 

- 7 

- 7 

615 

0 

-13 

-13 

M 

879 

0 

- 50 

- 50 

1971 

0 

-115 

-115 

257 

0 

-15 

-15 

536 

0 

-28 

-28 

N 

819 

0 

- 42 

- 42 

1888 

0 

- 97 

- 97 

181 

0 

-10 

-10 

531 

0 

-29 

-29 

0 

907 

0 

- 49 

- 49 

1404 

0 

- 75 

- 75 

271 

0 

-12 

-12 

511 

0 

-25 

-25 

IK 




— 9 




- 11 




- 2 




- 5 

17 




— 9 




— 10 




- 2 




- 5 

i a 




— 10 




— 10 




- 2 




- 5 

1 ^ 




— 8 




- 8 




+ 1 




- S 




— 6 




- 7 




+ 2 




- 4 

IQ 




// 




- 8 




+ 8 




- 2 

19 




/ 




+ 6 




+ 6 




+ 1 

11 




-f 1 




+ 11 




+ 6 




+ 4 





4 . 6 




+ IS 




+ 9 




+ 9 

9 




4 - fi 




+ 10 




+ 7 




+ 5 





4- ft 




+ 10 




+ 7 




+ 6 

7 




4 - 8 




+ 5 




+ 7 




+ 7 





4 - 7 




+ 6 




+ 8 




+ 8 





4- in 




+ 8 




+ 11 




+11 





4- 7 




+ 7 




+ 7 




+ 7 





4 - 8 




+ 6 




+ 5 




+ 5 





4 - 8 




+ 3 




+ 3 




+ 3 

i 




+ i 




+ i 




+ 1 




4* 1 

TWal 




_i_no 




- 26 




+163 




+ 106 

















































































































































































































































40 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com- 

pensa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

pensa- 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Lexington, Va., No. 

175 

Prestonsburg, Ky., No. 176 

Traverse City, 

Mich., No. 177 

Seney, Mich, No. 178 

A 

1063 

+ 2 

0 

4- 2 

634 

+ 2 

0 

4- 2 

591 

+ 2 

0 

4- 2 

733 

+ 2 

0 

+ 2 

B 

1063 

+ 64 

0 

+ 64 

634 

+56 

0 

+56 

591 

+58 

0 

+58 

730 

+60 

0 

+60 

C 

1063 

+108 

0 

+108 

634 

+76 

0 

+76 

600 

+72 

0 

+72 

730 

+84 

0 

+84 

D 

1063 

+ 94 

0 

+ 94 

750 

-*-36 

0 

+36 

580 

+39 

0 

+39 

730 

+51 

0 

+51 

E 

1000 

+ 46 

- 2 

+ 44 

744 

+ 16 

0 

+ 16 

581 

+ 16 

0 

+ 16 

730 

+26 

- 2 

+24 

F 

1030 

+ 18 

- 3 

+ 15 

860 

+ 9 

- 2 

+ 7 

572 

+ 4 

0 

+ 4 

700 

+ 9 

- 2 

+ 7 

G 

1058 

+ 4 

- 4 

0 

8S3 

+ 3 

- 3 

0 

581 

0 

0 

0 

700 

+ 2 

- 2 

0 

H 

1094 

+ 5 

- 5 

0 

869 

+ 4 

- 4 

0 

609 

+ 2 

- 2 

0 

700 

+ 3 

- 3 

0 

I 

1140 

+ 10 

-10 

0 

885 

+ 8 

- 8 

0 

592 

+ 5 

- 5 

0 

700 

4- 2 

- 7 

- 5 

J 

1312 

+ 3 

-16 

- 13 

900 

+ 6 

-16 

-10 

609 

0 

- 6 

- 6 

700 

+1 

-10 

- 9 

K 

1725 

+ 2 

-20 

- 18 

880 

+ 4 

-20 

-16 

648 

0 

-10 

-10 

700 

0 

-12 

-12 

1 . 

1725 

0 

-43 

- 43 

988 

0 

-24 

-24 

704 

0 

-17 

-17 

692 

0 

-16 

-16 

M 

1493 

0 

-84 

- 84 

1050 

0 

-59 

-59 

743 

0 

-41 

-41 

625 

0 

-35 

-35 

N 

1550 

0 

-81 

- 81 

1106 

0 

-56 

-56 

644 

0 

-33 

-33 

500 

0 

-28 

-28 

O 

1446 

0 

-75 

— 75 

1296 

0 

-69 

-69 

636 

0 

-37 

-37 

539 

0 

-27 

-27 

18 




- ii 




—14 




— 6 




- 6 

17 




- 10 




— 14 




— 6 




- 7 

16 




— 10 




—13 




— 6 





15 




- 7 




-10 




— 7 




- 7 

14 




- 6 




— 8 




— 8 




- 8 

13 




- 8 




—10 




-16 




-16 

12 




+ 7 




- 1 




— 11 




-11 

11 




+ 13 








— 6 




- 5 

10 




+ 16 




+10 




— 3 




- 2 

9 




+ 11 




+ 7 




0 




0 

8 




+ 10 




+ 7 




+ 5 




+ 6 

7 




+ 5 




+ 5 




+ 6 




+ 6 

6 




+ 6 




+ 6 




+ 7 




+ 7 

5 




+ 8 




+ 9 




+ 7 




+ 7 

4 




+ 7 




+ 7 




+ 5 




+ 6 

3 




+ 6 




-}- 6 




+ 5 




+ 5 

2 




+ 3 




4- 8 




+ 6 




+ 5 

1 




+ i 




+1 




+ 1 




+ 1 


















Total.. 




+ 54 




—45 




+ 19 




+69 

















Oconto, Wis., No. 179 

Grand Rapids 

Wis., No. 180 

Winona, Minn., No. 181 

Baldwin, Wis., No. 182 

A 

594 

+ 2 

0 

+ 2 

1004 

-f- 2 

0 

4- 2 

660 

+ 2 

0 

+ 2 

1122 

+ 2 

0 

+ 2 

B 

594 

4-58 

0 

+ 58 

1003 

+ 64 

0 

+ 64 

600 

+ 58 

0 

+58 

1122 

+ 64 

0 

+ 64 

C 

594 

-f- < 0 

0 

+ 70 

1000 

+ 104 

0 

+ 104 

660 

+76 

0 

+76 

1122 

+ 108 

0 

+ 108 

D 

600 

+40 

0 

+40 

1000 

+ 84 

0 

+ 84 

660 

+48 

0 

+ 48 

1120 

+ 102 

0 

+ 102 

E 

600 

+ 16 

0 

+ 16 

1000 

+ 40 

0 

+ 40 

656 

+ 20 

0 

+20 

1120 

+ 54 

- 2 

+ 52 

F 

600 

+ 5 

0 

+ 5 

1000 

+ 19 

- 2 

+ 17 

650 

+ 7 

- 2 

+ 5 

1100 

+ 23 

- 3 

+ 20 

G 

600 

+ 2 

- 2 

0 

1000 

+ 8 

- 4 

+ 4 

775 

+ 5 

- 3 

+ 2 

1100 

+ 10 

- 4 

+ 6 

H 

600 

+ 3 

- 3 

0 

1000 

+ 5 

- 5 

0 

931 

+ 5 

- 5 

0 

1100 

+ 6 

- 6 

0 

I 

600 

+ 6 

- 0 

0 

1000 

+ 9 

- 9 

0 

9S5 

+ 10 

-10 

0 

1100 

+ 5 

-10 

- 5 

J 

600 

0 

- 6 

- 6 

1000 

0 

-12 

- 12 

988 

0 

-10 

-10 

1100 

+ 2 

-12 

- 10 

K 

590 

0 

-10 

-10 

975 

0 

-16 

- 16 

985 

0 

-16 

-16 

1100 

0 

-17 

- 17 

L 

600 

0 

-14 

-14 

979 

0 

-23 

- 23 

1004 

0 

-24 

-24 

1054 

0 

-24 

- 24 

M 

679 

0 

-36 

-36 

1029 

0 

-56 

— 56 

993 

0 

—56 

-56 

921 

0 

-53 

- 53 

N 

688 

0 

-37 

-37 

969 

0 

-48 

- 48 

1081 

0 

-50 

-50 

1006 

0 

-49 

- 49 

0 

900 

0 

—53 

-53 

1021 

0 

-58 

- 58 

1096 

0 

-59 

-59 

1079 

0 

—56 

- 56 

18 




- 9 




- 10 




— 11 




— 11 

17 




- 9 




- 10 




— 11 




— 12 

16 




- 8 




- 9 




— 11 




— 11 

15 




- 7 




— 9 




— 11 




— 12 

14 




- 8 




- 9 




— 11 




— 12 

13 




-17 




- 18 




—19 




— 21 

12 




-11 




- 12 




—13 




— 15 

11 




- 7 




- 7 




— 8 




— 11 

10 




- 6 




- 5 




— 6 




— 9 

9 




- 1 




- 2 




— 3 




— 5 

8 




+ 3 




+ S 




4- 8 




0 

7 




+ 6 




4- 6 




4- 6 




4- 6 

6 




+ 8 




4- 8 




4- 9 




4- 9 

5 




+ 8 




+ 9 




4-10 




4- 10 

4 




+ 6 




+ 6 




4- 6 




4 - 6 

3 




+ 4 




+ 4 




4- 4 




+ 4 

2 




+ 4 




+ 4 




+ 4 




4 - i 

1 




+ / 




+ 1 




+ 1 




4- 1 

















Total.. 




- 7 




+ 52 




—65 




+ 61 


















> 


















































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


41 


Mean elevations and corrections for to-pography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva- 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

i 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Cumberland, 

Wis., No. 183 

Cambridge, Minn., No. 184 

Brainerd, Minn., No. 185 

Aberdeen, S. Dak., No. 186 

A 

1246 

+ 2 

0 

4* 2 

994 

4- 2 

0 

+ 2 

1205 

4- 2 

0 


1299 

+ 2 

0 

4- 2 

B 

1246 

+ 64 

0 

+ 64 

994 

+ 64 

0 

+ 64 

1205 

+ 64 

0 

+ 64 

1300 

+ 64 

0 

+ 64 

C 

1246 

+ 116 

0 

+ 116 

994 

+ 104 

0 

+ 104 

1210 

+ 116 

0 

+116 

1300 

+ 120 

0 

+ 120 

D 

1250 

+ 114 

0 

+ 114 

1000 

+ 84 

0 

+ 84 

1204 

+ 108 

0 

+ 108 

1300 

+ 120 

0 

+ 120 

E 

1250 

+ 66 

- 2 

+ 64 

1000 

+ 42 

- 2 

+ 40 

1200 

+ 62 

- 2 

+ 60 

1300 

+ 66 

- 2 

+ 64 

F 

1200 

+ 24 

- 4 

+ 20 

1000 

+ 20 

- 3 

+ 17 

1200 

+ 23 

- 3 

+ 20 

1300 

+ 34 

- 4 

+ 30 

G 

1200 

+ 10 

- 4 

+ 6 

1000 

+ 8 

- 4 

+ 4 

1200 

+ 10 

- 4 

+ 6 

1305 

+ 15 

- 5 

+ 10 

H 

1200 

+ 6 

- 6 

0 

1000 

+ 5 

- 5 

0 

1200 

+ 12 

- 6 

+ 6 

1305 

+ 6 

- 6 

0 

I 

1200 

+ 5 

-11 

- 6 

1000 

+ 9 

- 9 

0 

1200 

+ 5 

-11 

- 6 

1304 

+ 12 

-12 

0 

J 

1200 

+ 3 

-13 

- 10 

1000 

0 

-12 

- 12 

1200 

+ 3 

-13 

- 10 

1314 

0 

-16 

- 16 

K 

1200 

+ 2 

-20 

- 18 

1000 

0 

-16 

- 16 

1200 

+ 2 

-20 

- 18 

1332 

0 

-20 

- 20 

L 

1200 

0 

-29 

- 29 

958 

0 

-24 

- 24 

1200 

0 

-29 

- 29 

1335 

0 

-32 

- 32 

M 

1100 

0 

-61 

- 61 

971 

0 

-56 

- 56 

1221 

0 

-68 

- 68 

1354 

0 

-76 

- 76 

N 

1056 

0 

-53 

- 53 

1050 

0 

-49 

- 49 

1269 

0 

-65 

- 65 

1606 

0 

-83 

- 83 

0 

1071 

0 

-58 

- 58 

1100 

0 

-57 

- 57 

1200 

0 

-70 

- 70 

1586 

0 

-92 

- 92 

18 




- 11 




- 11 




- 12 




- 15 

17 




- 11 




— 11 




- 12 




— 15 

16 




- 12 




- 12 




- 12 




- 16 

15 




- 11 




- IS 




- 12 




- 16 

14 




- 11 




- IS 




- IS 




- 21 

13 




- 20 




— 20 




- 21 




- 34 

12 




- H 




- IS 




- 15 




- 22 

11 




- li 




- 12 




- IS 




- 21 

10 




- 9 




- 9 




- 11 




- 15 

9 




- 4 




- 5 




- 6 




- 8 

8 




0 




0 




- 1 




- S 

7 




4- 6 




+ 0 




4- 5 




+ 6 

6 




+ 9 




+ 9 




+ 9 




+ 9 

5 




+ 10 




+ 10 




+ to 




+ 11 

4 




+ 6 




+ e 




+ 6 




+ 7 

3 




4- L 




+ 4 




+ 4 




+ 4 

2 




4- 1 




+ i 




+ 4 




+ 3 

1 




1 ^ 




4- i 




+ i 




+ 1 
















Total 




+ 77 




+ 20 




+ 27 




- 54 


















Faith, S. Dak., No. 187 

Marmarth, N. 

Dak., No. 188 

Towner, N. Dak., No 

. 189 

Crosby, N. Dak., No. 190 

A 

2580 

+ 2 

0 

+ 2 

2696 

4- 2 

0 

+ 2 

1479 

4- 2 

0 

+ 2 

1962 

4- 2 

0 

4- 2 

B 

2580 

+ 68 

0 

+ 68 

2700 

+ 68 

0 

+ 68 

1479 

+ 64 

0 

+ 64 

1968 

+ 68 

0 

+ 68 

C 

2580 

+ 148 

0 

+ 148 

2700 

+148 

0 

+ 148 

1479 

+ 124 

0 

+ 124 

1970 

+ 138 

0 

+ 138 

D 

2600 

+221 

- 3 

+218 

2700 

+225 

- 3 

+222 

1480 

+ 140 

- 2 

+ 138 

1970 

+ 182 

- 2 

+ 180 

E 

2600 

+ 198 

- 6 

+192 

2700 

+201 

- 5 

+196 

1500 

+ 82 

- 2 

+ 80 

2000 

+130 

- 4 

+ 126 

F 

2600 

+108 

- 8 

+ 100 

2700 

+ 113 

- 8 

+ 105 

1500 

+ 39 

- 4 

+ 35 

2000 

+ 66 

- 6 

+ 60 

G 

2500 

+ 47 

- 9 

+ 38 

2700 

+ 58 

- 10 

+ 48 

1500 

+ 17 

- 5 

+ 12 

2000 

+ 31 

- 7 

+ 24 

H 

2500 

+ 28 

- 12 

+ 16 

2700 

+ 37 

- 13 

+ 24 

1500 

+ 14 

- 7 

+ 7 

2000 

+ 16 

- 10 

+ 6 

I 

2565 

+ 25 

- 25 

0 

2800 

+ 26 

- 26 

0 

1500 

+ 14 

-14 

0 

1980 

+ 20 

- 20 

0 

J 

2525 

+ 11 

- 27 

- 16 

2800 

+ 10 

- 26 

- 16 

1500 

0 

-16 

- 16 

1969 

+ 8 

- 20 

- 12 

K 

2500 

+ 7 

- 40 

- 33 

2800 

+ 10 

- 46 

- 36 

1500 

0 

-23 

- 23 

1970 

+ 4 

- 30 

- 26 

L 

2417 

+ 6 

- 59 

- 53 

3033 

+ 6 

- 73 

- 67 

1500 

0 

-36 

- 36 

1988 

+ 3 

— 45 

— 42 

M 

2293 

+ 3 

-132 

-129 

3193 

+ 8 

-188 

-180 

1629 

0 

-89 

- 89 

1993 

+ 2 

-112 

-110 

N 

2356 

0 

-117 

-117 

3000 

+ 3 

-158 

-155 

1775 

0 

-90 

- 90 

2038 

0 

-104 

-104 

O 

2589 

0 

-129 

-129 

2800 

0 

-135 

-135 

1721 

0 

—95 

- 95 

2007 

0 

-100 

-100 

IS 




— 29 




- 27 




- 17 




- 20 





— 29 




- 27 




- 16 




- 20 





— 28 




- 28 




- 16 




- 21 





— SO 




- 28 




- 18 




- 22 





— SI 




- 29 




- 19 




— 22 





— 19 




- 65 




- S 6 




- 43 





— 31 




- 34 




- 23 




- so 

1 1 




— 27 




- 28 




- 19 




- 24 

A L 




— 18 




- 19 




- 17 




- 19 





— 7 




- 9 




- 11 




- 15 





— / 




0 




- 4 




- 2 





4- 6* 




4- 6 




+ 4 




+ 5 





4- 9 




+ 9 




+ 10 




+ 10 





4- 10 




+ 10 




+ 10 




+ 9 





4- 7 




+ 7 




+ 7 




+ 7 





4 - A 




+ 4 




+ 3 




+ 3 





4- 8 




+ 3 




+ 4 




+ 4 

1 




+ i 




+ / 




+ 1 




+ 1 





+ 65 




- 20 




- 44 




+ 8 

A UtUl. 

. 





































































































































































































































U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40 


jo 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

pensa- 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Crookston, Minn., No. 191 

Poplar, Mont., No. 192 

Miles City, Mont., No. 193 

Huntley, Mont., No. 194 

A 

854 

+ 2 

0 

+ 2 

1996 

+ 2 

0 

+ 2 

2354 

4- 2 

0 

+ 2 

3016 

+ 2 

0 

+ 2 

B 

854 

+62 

0 

+62 

2000 

+ 68 

0 

+ 68 

2355 

+ 68 

0 

+ 68 

3020 

+ 67 

0 

+ 67 

C 

854 

+92 

0 

+92 

1992 

+ 138 

0 

+138 

2355 

+142 

0 

+142 

3019 

+154 

0 

+154 

D 

850 

+69 

0 

+69 

1992 

+ 182 

- 2 

+180 

2357 

+207 

0 

+207 

3018 

+243 

- 3 

+240 

E 

850 

+30 

- 2 

+28 

1972 

+136 

- 4 

+132 

2375 

+169 

- 5 

+ 164 

2961 

+232 

- 8 

+224 

F 

850 

+12 

- 2 

+10 

1968 

+ 66 

- 6 

+ 60 

2400 

+ 84 

- 7 

+ 77 

2990 

+132 

- 10 

+122 

G 

S50 

+ 6 

- 3 

+ 3 

1978 

+ 31 

- 7 

+ 24 

2600 

+ 43 

- 12 

+ 31 

3029 

+ 72 

- 12 

+ 60 

H 

850 

+ 4 

- 4 

0 

1985 

+ 16 

- 10 

+ 6 

2700 

+ 30 

- 16 

+ 14 

3075 

+ 46 

- 16 

+ 30 

I 

850 

+ 8 

- 8 

0 

2019 

+ 20 

- 20 

0 

2800 

+ 12 

- 20 

- 8 

3120 

-j- 24 

- 27 

- 3 

J 

888 

+ 1 

- 9 

- 8 

2074 

+ 6 

- 22 

-16 

2800 

+ 9 

- 29 

- 20 

3200 

+ 15 

- 33 

- 18 

K 

895 

0 

-14 

-14 

2105 

+ 6 

- 32 

- 26 

2825 

+ 6 

- 46 

- 40 

3355 

4* 8 

- 47 

- 39 

L 

925 

0 

-23 

-23 

2204 

+ 5 

- 53 

- 48 

2879 

+ 6 

- 70 

- 64 

3529 

+ 10 

- 85 

- 75 

M 

950 

0 

-56 

-56 

2221 

0 

-124 

-124 

3021 

+ 9 

-180 

-171 

3664 

+ 10 

-218 

-208 

N 

1056 

0 

-53 

-53 

2!00 

0 

-120 

-120 

3156 

0 

-162 

-162 

3750 

0 

-192 

-192 

0 

1229 

0 

-69 

-69 

2529 

0 

-117 

-117 

3257 

0 

-156 

-156 

4575 

0 

-219 

-219 

IS 




-12 




— 26 




- 31 




— 48 

17 




-12 




- 28 




- 31 




— 49 

16 




-13 



. 

- 26 




- 34 




— 49 

15 




-IS 




- 28 




- 36 




— A7 

14 




-14 




- 28 




- 37 




— U 

13 




-25 




- 57 




- 64 




— 78 

12 




-15 




- 85 




- 38 


• 


— A3 

11 




-u 




- 28 




- 31 




— 32 

10 




-14 




- 20 




— 20 




— 19 

9 



- 8 




- 12 




- 8 




— 6 

8 



- 4 




+ 1 




+ 3 




4- A 

7 




+ 4 




+ o 




+ 5 




-4- 6 

6 




+10 




+ 10 




+ 10 




-f 9 

5 




+10 




+ 9 




+ .9 


/ 


4- 9 

4 




+ 7 




+ 7 




+ 7 




+ 7 

3 




+ 3 



+ 3 




+ 3 




4- / 

2 




+ 4 



+ 4 




+ 4 




-f 3 

1 




+ i 



+ 1 




+ 1 




+ i 















Total 




-62 




- 87 




—204 




-222 


















Lander, Wyo., No. 195 

Farihault, Minn., No. 196 

St. James, Minn., No. 197 

Edgemont, S. Dak., No. 198 

A 

5365 

+ 2 

0 

+ 2 

989 

+ 2 

0 

+ 2 

1083 

+ 2 

0 

+ 2 

3499 

+ 2 

0 

+ 2 

B 

5370 

+ 67 

0 

+ 67 

989 

+ 64 

0 

+ 64 

1083 

+ 61 

0 

+ 64 

3495 

+ 66 

0 

+ 66 

C 

5370 

+ 164 

- 4 

+ 160 

1000 

+ 103 

0 

+103 

1080 

+108 

0 

+108 

3472 

+ 157 

- 1 

+ 156 

D 

5372 

+306 

- 6 

+300 

988 

+ 84 

0 

+ 84 

1072 

+ 95 

0 

+ 95 

3475 

+256 

- 5 

+251 

E 

5376 

+391 

- 8 

+383 

1000 

+ 42 

- 3 

+ 39 

1075 

+ 49 

- 2 

+ 47 

3481 

+273 

- 8 

+265 

F 

5400 

+308 

- 20 

+288 

1025 

+ IS 

- 3 

+ 15 

1082 

+ 23 

- 3 

+ 20 

3504 

+ 166 

- 10 

+156 

G 

5383 

+ 189 

- 24 

+ 165 

1016 

+ 7 

- 4 

+ 3 

1079 

+ 9 

- 4 

+ 5 

3543 

+ 82 

- 12 

+ 70 

H 

5569 

+ 137 

- 32 

+105 

1062 

+ 4 

- 5 

- 1 

1069 

+ 4 

- 4 

0 

3578 

+ 46 

- 16 

+ 30 

1 

5915 

+ 97 

- 13 

+ 54 

1075 

+ 8 

- 9 

- 1 

loss 

+ 9 

- 9 

0 

3640 

+ 45 

- 30 

+ 15 

J 

6125 

+ 58 

- 66 

- 8 

1103 

0 

- 11 

- 11 

1100 

+ 1 

- 11 

- 10 

3725 

+ 22 

- 40 

- 18 

K 

6470 

+ 47 

-109 

- 62 

1112 

0 

- 18 

- 18 

1115 

0 

- 16 

- 16 

3820 

+ 15 

- 60 

- 45 

L 

6875 

■+• 22 

-158 

-136 

1096 

0 

- 26 

- 26 

1129 

0 

- 27 

- 27 

3838 

+ 18 

- 94 

- 76 

M 

7279 

+ 15 

-425 

-410 

1079 

0 

- 59 

- 59 

10 S 6 

0 

- 60 

- 60 

4100 

+ 14 

-245 

-231 

N 

7138 

+ 8 

-373 

-365 

1050 

0 

- 53 

- 53 

1156 

0 

- 57 

- 57 

4288 

4 5 

-225 

-220 

0 

7096 

0 

-341 

-341 

1021 

0 

- 56 

- 56 

1225 

0 

- 61 

- 61 

4150 

+ 6 

-208 

-202 

18 




- 68 




- 11 




- 12 




41 

17 




- 68 




- 11 




- 12 




41 

16 




- 71 




- 12 




— 12 




41 

15 




- 66 




- 13 




— 12 





14 




- 61 




- 18 




— 14 




44 

// 

13 




- 88 




- 21 




— 23 




6Q 

12 




- 51 




- 15 




— 15 




AO 

11 




- 37 




- 11 




— 13 




4 V 

81 

10 




- 17 




- 9 




— 11 




20 

9 




0 




- 6 




— 6 




ft 

8 




+ 8 




0 




— 1 




-4- 

7 




+ 7 




+ 6 




4 . 6 




4> ft 

6 




+ 9 




+ 9 




-f 9 




4- Q 

5 




+ 9 




+ 10 




+ 10 




4_ m 

4 




+ 8 




+ 6 




4- 6 




4- 7 

3 








+ 4 




4- / 




U_ / 

2 




+ 3 




+ 4 




4- A 




■ 4 

4- 8 

1 




+ 1 




+ l 




+ l 




+ i 
















Total. 




—275 




+ 4 




+ 19 




-115 













. | . 
















































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 43 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Dawson, Minn., No. 

199 

Cokato, Minn., No. 200 

Wasta, S. Dak., No. 201 

Moorcroft, Wyo., No. 202 

A 

1059 

+ 2 

0 

+ 2 

1059 

+ 2 

0 

+ 2 

2317 

4- 2 

0 

+ 2 

4249 

+ 2 

0 

+ 2 

B 

1060 

+ 64 

0 

+ 64 

1060 

+ 64 

0 

+ 64 

2320 

+ 68 

0 

+ 68 

4250 

+ 68 

0 

+ 68 

C 

1052 

+106 

0 

+ 106 

1052 

+ 106 

0 

+ 106 

2320 

+ 144 

0 

+ 144 

4239 

+ 162 

_ o 

4J 

+160 

D 

1058 

+ 93 

0 

+ 93 

1058 

+ 90 

0 

+ 90 

2320 

+ 198 

0 

+ 198 

4236 

+282 

- 6 

+276 

E 

1050 

+ 47 

- 2 

+ 45 

1044 

+ 42 

- 2 

+ 40 

2355 

+165 

— 5 

+ 160 

4250 

+322 

- 8 

+314 

F 

1056 

+ 23 

- 3 

+ 20 

1048 

+ 23 

- 3 

+ 20 

2400 

+ 88 

— 6 

+ 82 

4300 

+222 

- 10 

+212 

O 

1076 

+ 9 

- 4 

+ 5 

IMS 

+ 9 

- 4 

+ 5 

2400 

+ 42 

- 8 

+ 34 

4300 

+ 120 

- 12 

+108 

H 

1081 

+ 6 

- 5 

4* 1 

1053 

+ 5 

— 5 

0 

2100 

+ 21 

- 11 

+ 10 

4300 

+ 72 

- 16 

+ 56 

I 

1094 

+ 9 

- 9 

0 

1048 

+ 9 

- 9 

0 

2500 

+ IS 

- 20 

- 2 

4300 

+ 70 

- 40 

+ 30 

J 

1097 

+ 2 

-12 

- 10 

10-11 

+ 5 

-11 

- 6 

2500 

+ 7 

- 24 

- 17 

4300 

+ 40 

- 48 

- 8 

K 

1102 

0 

-18 

- 18 

1040 

+ 2 

-16 

- 14 

2500 

+ 5 

- 40 

- 35 

4320 

+ 21 

- 62 

- 41 

L 

1129 

0 

-27 

- 27 

1042 

0 

-24 

- 24 

2600 

+ 6 

- 62 

- 56 

4521 

+ 20 

-107 

- 87 

M 

1200 

0 

-66 

- 66 

1036 

0 

-57 

- 57 

2586 

0 

-151 

-151 

4657 

+ 19 

-272 

—253 

N 

1331 

0 

—65 

— 65 

1044 

0 

-53 

- 53 

2862 

+ 2 

-149 

-147 

4588 

+ 5 

-240 

-235 

0 

1350 

0 

-71 

- 71 

1121 

0 

-56 

— 56 

3082 

0 

-156 

-156 

4321 

0 

-214 

-214 

18 




- 13 




- 12 




- 31 




— 44 

17 




- 12 




- 12 




— 32 




— 44 

16 




- 13 




- 13 




— 32 




— 41 

15 




- u 




- 12 




— 3A 




— AS 

14 




- 16 




- 14 




— 85 




— A3 

13 




- 27 




- 22 




— 55 




— 68 

12 




- IS 




- 15 




— 33 




— 39 

11 




- 16 




- IS 




— 29 




— 31 

10 




- 13 




— 11 




— 18 




— 19 

9 




- 7 




- 6 




- 6 




— 6 

8 




- 2 




- 1 




+ 1 




+ 8 

7 




+ 6 




+ 6 




+ 6 




4 - 6 

6 




+ 9 




+ 9 




+ 9 




+ 9 

5 




+ 10 




+ 10 




+ 10 




+ to 

4 




+ 6 




+ 6 




+ 7 




4- 7 

3 




+ ^ 




+ 4 




+ 4 




+ 4 

2 




4- i 




+ 4 




4- 8 




+ 8 

1 




+ i 




+ l 




+ i 




+ 1 


















Total.. 




- 32 




+ 26 




-130 




+ 50 

















Duluth, Minn., No. 203 

Osage, Iowa, No. 204 

Randolph, Nebr., No. 205 

Valentine, Nebr., No. 206 

A 

708 

+ 2 

0 

.+ 2 

1167 

4- 2 

0 

+ 2 

1689 

4~ 2 

0 

+ 2 J 

2576 

+ 2 

0 

4- 2 

B 

705 

+60 

0 

+ 60 

1170 

+ 64 

0 

+ 64 

1684 

+ 68 

0 

+ 68 

2576 

+ 68 

0 

+ 68 

C 

708 

+80 

0 

+ 80 

1170 

+ 112 

0 

+ 112 

1688 

+ 132 

0 

+ 132 

2576 

+ 148 

0 

+ 148 

D 

752 

+46 

0 

+ 46 

1200 

+ 102 

0 

+ 102 

1659 

+ 158 

- 2 

+ 156 

2576 

+ 219 

- 3 

+216 

E 

806 

+22 

- 2 

+ 20 

1200 

+ 56 

- 3 

+ 53 

1700 

+ 107 

- 4 

+ 103 

2575 

+ 191 

- 5 

+186 

F 

834 

+12 

- 2 

+ 10 

1200 

+ 23 

- 4 

+ 19 

1700 

+ 50 

- 5 

+ 45 

2580 

+ 106 

- 8 

+ 98 

G 

871 

+ 4 

- 3 

+ 1 

1200 

+ 11 

- 4 

+ 7 

1700 

+ is 

- 6 

+ 12 

2575 

+ 48 

- 12 

+ 36 

H 

900 

+ 2 

- 5 

- 3 

1200 

+ 7 

- 6 

+ 1 

1700 

+ 10 

- 8 

+ 2 

2600 

+ 32 

- 12 

+ 20 

I 

932 

+ 5 

- 8 

- 3 

11 SO 

+ 11 

-11 

0 

1700 

+ 12 

-12 

0 

2630 

+ 23 

- 23 

0 

J 

969 

+ 1 

-11 

- 10 

1150 

+ 1 

-11 

- 10 

1631 

+ 5 

-16 

- 11 

2638 

+ 12 

- 28 

- 16 

K 

965 

+ 1 

-15 

- 14 

1130 

+ 1 

-18 

- 17 

1620 

+ 4 

-25 

- 21 

2685 

+ 11 

- 44 

- 33 

L 

1071 

0 

-25 

- 25 

1142 

+ 3 

-27 

- 24 

1617 

+ 2 

-39 

- 37 

2762 

+ 6 

- 66 

- 60 

M 

1093 

0 

—65 

— 65 

1129 

0 

-64 

- 64 

1514 

+ 2 

-88 

- 86 

2721 

+ 5 

-157 

-152 

N 

1162 

0 

-59 

- 59 

1056 

0 

-52 

- 52 

1512 

0 

-79 

- 79 

2644 

+ 5 

-139 

-134 

O 

1186 

0 

-67 

- 67 

968 

0 

-56 

- 56 

1539 

0 

-86 

- 86 

2496 

+ 3 

-125 

-122 

18 




— 11 




- 10 




- 16 




- 25 

17 




— 11 




- 10 




- 17 




- 25 

16 




- 11 




- 10 




- 17 




- 25 

15 




— 12 




- 11 




- 20 




- 28 

14 




- 11 




- 12 




- 21 




- 28 

13 




— 18 




- 20 




- 36 




- 49 

12 




- 13 




- H 




- 22 




- 29 

11 




— 11 




- 11 




- 20 




- 26 

10 




— 10 




- 8 




- u 




- 17 

9 




— 6 




- 4 




- 6 




- 6 

g 




— 1 




+ 2 




0 




0 

7 




+ 5 




+ 6 




+ 7 




+ 6 

0 




+ 9 




+ 9 




+ 9 




+ 9 

5 




+ 9 




+ 10 




+ 10 




+ 11 

4 




+ 6 




+ 6 




+ 7 




+ 7 

3 




-f A 








+ 4 




+ 4 

2 




+ i 




+ 4 




+ 4 




+ S 

i 




+ i 




+ l 




+ i 




+ 1 




















—103 




+ 69 




+ 53 




+ 40 



1 



1 





















































































































































































































































44 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


Mean elevations and corrections for topography and isostatic compensation , separate zones, for United States stations —Contd. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 


Wheeling, W. Va., No. 207 

Leon, Iowa, No. 208 

Laurel, Md., No. 209 

Harrisburg, Pa., No. 210 

A 

674 

+ 2 

0 

4- 2 

1127 

4- 2 

0 

+ 

2 

176 

+ 2 

0 

+ 2 

340 

4“ 2 

0 

+ 2 

B 

676 

+59 

0 

+59 

1130 

+ 63 

0 

+ 

63 

180 

+36 

0 

+36 

344 

+52 

0 

+52 

C 

676 

+ 78 

0 

+78 

1114 

+ 108 

0 

+108 

168 

+16 

0 

+ 16 

344 

+38 

0 

+38 

D 

662 

+48 

0 

+48 

1067 

+ 96 

0 

+ 

96 

162 

+ 3 

0 

+ 3 

347 

+ 13 

0 

+ 13 

E 

694 

+ 18 

0 

+ 18 

1100 

+ 56 

- 2 

+ 

54 

173 

+ 1 

0 

4* 1 

318 

+ 9 

0 

+ 9 

F 

808 

+ 9 

- 2 

+ 7 

1100 

+ 24 

- 3 

+ 

21 

206 

+ 1 

- 1 

0 

333 

+ 1 

- 1 

0 

G 

873 

+ 5 

- 3 

+ 2 

1100 

+ 9 

- 4 

+ 

5 

232 

0 

- 1 

- 1 

389 

+ 1 

- 1 

0 

H 

978 

+ 3 

- 5 

- 2 

1100 

+ 8 

- 5 

+ 

3 

251 

0 

- 1 

- 1 

386 

+ 1 

- 2 

- 1 

I 

1002 

+ 2 

- 9 

- 7 

1100 

+ 6 

- 9 


3 

261 

0 

— 2 

- 2 

472 

0 

- 4 

- 4 

J 

1059 

+ 1 

-12 

-11 

1100 

+ 2 

-11 

— 

9 

262 

0 

- 3 

- 3 

542 

0 

- 6 

- 6 

K 

1070 

4“ 1 

-17 

-16 

1100 

+ 2 

-18 

_ 

16 

270 

0 

- 4 

- 4 

582 

0 

- 9 

- 9 

L 

1112 

+ 2 

-27 

-25 

1082 

+ 2 

-26 

_ 

24 

265 

0 

- 6 

- 6 

604 

0 

-14 

-14 

M 

1100 

+ 2 

-65 

-63 

1057 

+ 1 

-58 

_ 

57 

186 

0 

-11 

-11 

686 

0 

-39 

-39 

N 

1013 

0 

-51 

-51 

1012 

0 

-52 

— 

52 

262 

0 

-13 

-13 

762 

0 

-38 

-38 

0 

1196 

0 

-60 

-60 

943 

0 

-50 


50 

413 

0 

-21 

-21 

759 

0 

-38 

-38 

18 




-13 





9 




- 7 




— 10 

17 




-13 





9 




- 8 




— 10 

16 




-13 





9 




- 8 




— 9 

15 




-11 





to 




- 8 




— 7 

14 




-10 





11 




- 4 




— A 

13 




-IS 





20 




+ 5 




4- 3 

12 




- s 





IS 




+14 




+ 11 

11 




+ 4 





IS 




+ 18 




4-1A 

10 




+ 8 




. 

12 




+ 17 




+1A 

9 




+ 7 





6 




+ 10 




4- 9 

8 




+ 8 





0 




+ 12 




+ 12 

7 




+ 5 




4- 

8 




+ 6 




4- 6 

6 




+ 6 




4- 

9 




+ 6 




4- 6 

5 




+ 8 




4- 

11 




+ 7 

. 



4- 7 

4 




+ 7 




+ 

7 




+ 8 




4- 6 

3 




+ 6 




4- 

5 




+ 6 




4- 6 

2 




+ 3 




4- 

3 




+ 4 




4- I. 

1 




+ 1 




+ 

1 




+ 1 




+1 

















Total.. 




-34 




+ 

73 




+73 




+24 

















Pittsburg, Pa., No. 211 

Rockville, Md., No. 212 

Upper Marlboro, Md., No. 213 

Fairfax, Va., No. 214 

A 

772 

+ 2 

0 

+ 2 

422 

+ 2, 

0 

+ 

2 

38 

4- 2 

0 

+ 2 

378 

+ 2 

0 


B 

772 

+ 60 

0 

+60 

424 

+56 

0 

+ 

56 

40 

+ 12 

0 

+ 12 

372 

+53 

0 

+ 53 

C 

778 

+87 

0 

+87 

429 

+ 50 

0 

+ 

50 

35 

+ 1 

0 

+ 1 

350 

+40 

0 

+ 40 

D 

777 

+61 

- 1 

+60 

425 

+22 

0 

+ 

22 

32 

0 

0 

0 

361 

+ 16 

0 

+ 16 

E 

850 

+26 

- 2 

+24 

418 

+ 8 

0 

+ 

8 

09 

0 

0 

0 

359 

+ 10 

- 1 

+ 9 

F 

865 

+ 13 

- 3 

+ 10 

401 

+ 3 

- 1 

+ 

2 

90 

0 

0 

0 

352 

+ 2 

- 1 

+ 1 

G 

925 

+ 4 

- 3 

+ 1 

381 

+ 1 

- 1 


0 

94 

0 

0 

0 

358 

+ 1 

- 1 

0 

H 

966 

+ 4 

- 5 

- 1 

385 

+ 1 

- 2 

— 

1 

100 

0 

- 1 

- 1 

345 

+ 1 

- 2 

- 1 

I 

990 

+ 4 

- 8 

- 4 

372 

0 

- 3 

— 

3 

121 

0 

- 1 

- 1 

302 

0 

- 2 

- 2 

J 

1031 

+ 2 

-11 

- 9 

365 

0 

- 4 

— 

4 

124 

0 

- 1 

- 1 

275 

0 

- 3 

- 3 

K 

1050 

+ 1 

-17 

-16 

368 

0 

- 6 

_ 

6 

140 

0 

- 2 

- 2 

262 

0 

- 4 

- 4 

L 

1075 

0 

-26 

-26 

360 

0 

- 9 

— 

9 

90 

0 

- 2 

- 2 

210 

0 

- 5 

- 5 

M 

986 

0 

-58 

-58 

246 

0 

-14 

— 

14 

61 

0 

- 3 

- 3 

278 

0 

-16 

- 16 

N 

1200 

0 

-61 

-61 

342 

0 

-17 

— 

17 

157 

0 

- 8 

- 8 

370 

0 

-19 

- 19 

o 

1236 

0 

-62 

-62 

497 

0 

-25 

— 

25 

310 

0 

-16 

-16 

520 

0 

-26 

- 26 

18 




-11 




_ 





— 6 




7 

17 

. 



-12 




_ 

8 




— 7 




g 

16 




-13 




_ 

8 




— 8 




Q 

15 




-10 




_ 

8 








0 

14 




- 9 




_ 

4 




— l 





13 




-11 




+ 

2 




4- 7 




n 

12 

. 



- 1 




4- 

12 




4 -is 





11 




+ 4 




4- 

17 




+19 




4 - 17 

10 




+ 9 




+ 

17 




+ 17 




4- 17 

9 




+ 7 




+ 

11 




+11 




4- 11 

8 




+ 9 




+ 

12 




+12 




4 - 19 

7 




+ 5 




+ 

6 




+ 6 





6 




+ 6 




+ 

6 




4- 6 




5 




+ 8 




+ 

7 




4- 7 

. 



4 




+ 7 




+ 

6 




4- 6 




4- ft 

3 




+ 6 




+ 

6 




4- 6 




4- ft 

2 




+ 3 




+ 

4 




-4- A 





1 




+ 1 




+ 

1 




+1 




4 - 4 
4- 1 















Total.. 


.!. 

1 

+ 5 




+133 




+71 




+ 114 

































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 45 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for United States stations— Contd. 


Zone 

Ele¬ 

va¬ 

tion 

in 

feet 

To- 

pog- 

ra- 

phy 

Cora- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Ele¬ 

va¬ 

tion 

in 

feet 

To- 

pog- 

ra- 

pby 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Ele¬ 

va¬ 

tion 

in 

feet 

To- 

pog- 

ra- 

phy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Ele¬ 

va¬ 

tion 

in 

feet 

To- 

pog- 

ra- 

pby 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Ele¬ 

va¬ 

tion 

in 

feet 

To- 

pog- 

ra- 

phy 

Com- 

pen- 

sa- 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Crisfield, Hd., No. 215 

Fredericksburg, Va., No. 
216 

Dover, Del., No. 217 

North Tamarack, 
No. 218 

Mich., 

Hagerstown 

, Md., 

No. 219 

A 

4 

+1 

0 

+ 

1 

52 

+ 2 

0 

+- 2 

38 

+ 2 

0 

+ 

2 

1215 

+ 

2 

0 

+ 

2 

544 

+ 2 

0 

+ 2 

B 

6 

0 

0 


0 

60 

+ 15 

0 

+15 

42 

+10 

0 


10 

1215 

+ 

64 

0 

+ 

64 

551 

+56 

0 

+56 

c 

4 

0 

0 


0 

54 

+ 2 

0 

+ 2 

40 

+ 1 

0 

+ 

1 

1212 

+ 114 

0 

+ 114 

556 

+ 64 

0 

+64 

D 

4 

0 

0 


0 

47 

0 

0 

0 

38 

0 

0 


0 

1212 

+ 111 

- 1 

+ 110 

559 

+36 

- 1 

+35 

E 

4 

0 

0 


0 

47 

0 

0 

0 

30 

0 

0 


0 

1207 

+ 

60 

- 3 

+ 

57 

559 

+ 17 

- 1 

+ 16 

F 

2 

0 

0 


0 

62 

0 

0 

0 

31 

0 

0 


0 

1198 

+ 

24 

- 4 

+ 

20 

556 

+ 4 

- 2 

+ 2 

G 

1 

0 

0 


0 

98 

0 

0 

0 

32 

0 

0 


0 

1148 

+ 

8 

- 4 

+ 

4 

560 

+ 2 

- 2 

0 

H 

1 

0 

0 


0 

138 

0 

- 1 

- 1 

28 

0 

0 


0 

1034 

+ 

8 

- 5 

+ 

3 

556 

+ 1 

- 3 

- 2 

I 

- 4 

0 

0 


0 

154 

0 

- 1 

- 1 

29 

0 

0 


0 

825 

+ 

7 

- 7 


0 

547 

+ 1 

- 5 

- 4 

J 

- 3 

0 

0 


0 

169 

0 

- 2 

- 2 

28 

0 

0 


0 

743 

+ 

1 

- 8 

- 

7 

553 

0 

- 6 

- 6 

K 

- 2 

0 

0 


0 

168 

0 

- 3 

- 3 

27 

0 

- 1 

_ 

1 

659 


0 

-11 


11 

692 

0 

-11 

-11 

L 

- 1 

0 

0 


0 

1 S1 

0 

- 4 

- 4 

28 

0 

- 1 

_ 

1 

632 


0 

-15 

_ 

15 

771 

0 

-18 

-18 

M 

- 3 

0 

0 


0 

152 

0 

- 9 

- 9 

27 

0 

- 1 

— 

1 

508 


0 

-30 

_ 

30 

807 

0 

-47 

-47 

N 

- 6 

0 

0 


0 

297 

0 

-15 

-15 

36 

0 

-12 

— 

12 

572 


0 

-30 

_ 

30 

769 

0 

-40 

-40 

0 

-26 

0 

+1 

+ 

1 

470 

0 

-24 

-24 

92 

0 

- 5 

— 

5 

596 


0 

-30 

- 

30 

923 

0 

-46 

-46 

18 




+ 

4 




- 5 





2 






8 




-10 

17 




+ 

5 




- 7 





2 





10 




— 9 

16 




+ 

8 




- 7 




-f 

1 





10 




— 9 

15 




-f 

10 




- 7 




-F 

3 





9 




— 7 

14 




+ 

12 




- 4 




-F 

6 





9 




— 6 

13 




+ 

25 




+ 4 




-F 

IS 





16 




— 1 

12 




+ 

23 




+u 




4- 

16 





12 




-F 9 

11 




+ 

23 




+17 




-F 

19 





8 




+14 

10 




4- 

18 




+18 




-F 

18 





5 




+ 15 

9 




+ 

13 




+ 12 




-F 

12 





2 




+10 

8 




+ 

14 




+12 




-F 

U 




-F 

S 




+11 

7 




+ 

5 




+ 5 




-F 

6 




-F 

6 




+ 6 

6 




-f* 

6 




+ 6 




-F 

6 




-F 

8 




+ 6 

5 




+ 

7 




+ 8 




-F 

6 




-F 

8 




+ 7 

4 




-f 

7 




+ 7 




-F 

6 




-F 

5 




-F 6 

3 




-f 

6 




+ 6 




-F 

6 




-F 

A 




+ 6 

2 




-F 

S 




-f s 




-F 

A 




-F 

A 




+ 4 

1 




+ 

1 




+ 1 




+ 

1 




+ 

1 




+ 1 





















Total. 




-1-192 




+43 




-4-126 




-4-201 




+55 
























MEAN ELEVATIONS AND CORRECTIONS FOR TOPOGRAPHY AND ISOSTATIC COMPENSATION FOR 

SEPARATE ZONES AT SELECTED STATIONS IN EUROPE. 

No doubt the Geodetic Survey of Canada will publish the data for the separate zones at 
stations in that country. The publication of the “Survey of India” ° does not give the effect 
of topography and compensation for the separate zones in India. 

For the purpose of testing the gravity height formula (see pp. 93 to 96) a number of European 
stations were reduced for topography and compensation by the Hayford method. The depth 
of compensation used was 113.7 km., the one on which the reduction tables in Special Publication 
No. 10 are based. 

It is believed that the elevations of the topography and the corrections for the separate 
zones as given in the following table are of sufficient interest and value for the purposes of 
further investigations to warrant their publication here. As in the preceding table the cor¬ 
rections given in the following table are in units of the fourth decimal place in dynes. Figures 
printed in italics represent values interpolated from surrounding stations according to methods 
explained in Special Publication No. 10, pages 58 to 65, or represent values found to be identical 
with those for a station very close by. 


a See Survey of India, Professional Paper No. 15, “The pendulum operations in India and Burma, 1908 to 1913,” by Capt. H. J. Couchman, 
R. E., Deputy Superintendent, Survey of India, Dehra Dun, India, 1915. 





















































































































































46 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40 


Mean elevations and corrections for topography and isostatic compensation, separate zones, for selected stations in Europe. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

pensar 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

pensa- 

tion 

Stilfserjoch, Austria (Stelvio 
Pass), No. 1 

Franzenhohe, 

Austria, 

No. 2 

Schneekoppe, Germany, No. 3 

Alter Bruch, Germany 

, No. 4 

A 

9055 

+ 2 

0 

+ 2 

7178 

+ 2 

0 

+ 2 

5266 

+ 2 

0 

+ 2 

3010 

+ 2 

0 

4- 2 

B 

9050 

+ 70 

- 4 

+ 66 

7130 

+ 68 

0 

+ 63 

5250 

+ 62 

0 

+ 62 

3000 

+ 62 

0 

+ 62 

C 

90S0 

+ 164 

- 8 

+ 1.56 

7180 

+ 164 

- 4 

+ 160 

5110 

+ 145 

- 4 

+ 141 

2980 

+ 148 

0 

+ 148 

D 

9160 

+342 

- 12 

+330 

7440 

+313 

- 6 

+ 307 

4700 

+262 

— 6 

+256 

2980 

+ 231 

0 

+231 

E 

8845 

+509 

- 16 

+493 

7500 

+450 

- 16 

+434 

4190 

+333 

- s 

+325 

2990 

+ 226 

- 8 

+218 

F 

8990 

+509 

- 2 S 

+481 

8140 

+373 

- 26 

+347 

4050 

+266 

- 10 

+256 

3140 

+ 126 

-10 

+ 116 

G 

8560 

+309 

- 30 

+339 

8440 

+259 

- 31 

+228 

3630 

+ 150 

- 12 

+ 138 

3440 

+ 61 

-12 

+ 49 

II 

8210 

+296 

- 42 

+254 

8750 

+ 190 

- 45 

+ 145 

3400 

+ 98 

- 16 

+ 82 

3190 

+ 28 

-16 

+ 12 

I 

7430 

+251 

- 66 

+ 185 

7840 

+ 164 

- 71 

*4“ 93 

2910 

+ 80 

- 28 

+ 52 

2510 

+ 35 

-22 

+ 13 

J 

7140 

+ 140 

- 74 

+ 66 

7440 

+ 90 

- 79 

+ n 

2300 

+ 35 

- 22 

+ 13 

2380 

+ 20 

-24 

- 4 

K 

7280 

+ 115 

-121 

- 6 

7130 

+ 77 

-118 

- 41 

2070 

+ 16 

- 20 

- 4 

1950 

+ 9 

-21 

- 12 

L 

7300 

4“ 74 

-174 

-100 

7220 

+ 52 

-172 

-120 

1S60 

+ 11 

- 38 

- 27 

1700 

0 

-34 

- 34 

M 

5990 

+ 60 

-339 

-279 

5990 

+ 45 

-313 

—29S 

1150 

+ 14 

- 63 

- 49 

1130 

+ 13 

-65 

- 52 

N 

4220 

+ 23 

-222 

-199 

4220 

+ 23 

-223 

-200 

840 

0 

- 44 

- 44 

860 

0 

-45 

- 45 

0 

2880 

0 

-140 

-140 

2880 

0 

-140 

-140 

880 

0 

- 51 

- 51 

900 

0 

-51 

- 51 

18 




- 27 




- 27 




- 8 




- 8 

17 




- 26 




- 26 




- 7 




— 7 

16 




- 26 




- 26 




- 7 




- 7 

15 




- 26 




- 26 




- 8 




- 8 

14 




- 21 - 




- 21 




- 8 




- 8 

13 




- 20 




- 20 




- 20 




- 20 

12 




- 4 




- 4 




- 12 




- 12 

11 




0 




0 




- 8 




- 8 

10 




+ 1 




+ 1 




- 4 




- 4 

9 




0 




0 




+ 2 




+ 2 

8 




+ 6 




+ 6 




4- 4 




+ 4 

7 




+ 4 




+ 4 




4 4 




+ 4 

6 




+ 2 




+ 2 




+ 2 




4 2 

5 




0 




0 




0 




0 

4 




+ 3 




+ 3 




+ 3 




4 3 

3 




+ 5 




+ 5 




+ 5 




+ 6 

2 




+ 5 




+ 5 




+ 5 




+ 6 

1 




+ 1 




+ 1 




+ 1 




+ 1 


















Total.. 




+ 1525 




+873 




+ 1096 




+597 
















Brocken, Germany, No. 5 

Seharfenstein, Germany, No. 6 

Naye, Switzerland, No. 7 

Villeneuve, Switzerland 

, No. 8 

A 

3740 

+ 2 

0 

+ 2 

2044 

+ 2 

0 

+ 2 

6520 

+ 2 

0 

+ 2 

1230 

+ 2 

0 

+ 2 

B 

3740 

+ 68 

0 

+ 68 

2020 

+ 61 

0 

+ 61 

6530 

+ 59 

0 

+ 59 

1250 

+ 62 

0 

+ 62 

C 

3700 

+ 154 

0 

+ 154 

1990 

+ 133 

0 

+ 133 

6430 

+ 157 

- 4 

+ 153 

1250 

+ 111 

0 

+ 111 

D 

3560 

+258 

- 6 

+252 

2025 

+ 181 

0 

+ 181 

5920 

+257 

- 6 

+ 251 

1200 

+ 109 

0 

+ 109 

E 

3240 

+278 

- 8 

+270 

2050 

+ 143 

- 7 

+ 136 

5410 

+385 

- 11 

+374 

1270 

+ 55 

0 

+ 55 

F 

2876 

+ 167 

- 10 

+ 157 

2078 

+ 70 

- 8 

+ 62 

4710 

+319 

— 15 

+304 

1720 

+ 19 

- 4 

+ 15 

G 

2450 

+ 85 

- 12 

+ 73 

2090 

+ 33 

- 9 

+ 24 

4300 

+201 

- 16 

+ 185 

2360 

- 10 

- 7 

- 17 

n 

2320 

+ 49 

- 16 

+ 33 

2100 

+ 18 

- 16 

+ 2 

4100 

+ 140 

- 22 

+ 118 

2820 

- 14 

- 16 

- 30 

I 

1980 

+ 52 

- 20 

+ 32 

1780 

+ 18 

- 14 

+ 4 

3820 

+ 111 

- 30 

+ 81 

3180 

- 22 

- 25 

- 47 

J 

1580 

+ 21 

- 16 

+ 5 

1460 

- 1 

- 15 

- 16 

3390 

+ 56 

- 35 

+ 21 

3420 

- 3 

- 35 

- 38 

K 

1170 

0 

- 10 

- 10 

1170 

0 

- 13 

- 13 

3950 

+ 55 

- 64 

- 9 

3730 

- 19 

- 57 

- 76 

L 

900 

0 

- 18 

- 18 

900 

0 

- 18 

- 18 

4310 

+ 38 

-102 

- 64 

4290 

- 15 

- 95 

-110 

M 

660 

+ 5 

- 35 

- 30 

660 

0 

- 35 

- 35 

4710 

+ 30 

-273 

-243 

4310 

- 14 

-251 

-265 

N 

600 

0 

- 31 

- 31 

600 

0 

- 31 

- 31 

5080 

+ 17 

-269 

-252 

5080 

+ 1 

-272 

-271 

O 

700 

0 

- 38 

- 38 

700 

0 

- 38 

- 38 

2700 

0 

-139 

-139 

2700 

0 

-139 

-139 

18 




- 6 




- 6 




— 25 




— 25 

17 




- a 




- 6 




— 24 




— 24 

16 




- 7 








— 25 




— 25 

15 




- 6 




- 6 




— 21 




— 21 

14 






. 






— 16 




— 16 

13 




- is 




- 13 




— 18 




— IS 

12 




- 15 




- 15 




— 6 




— 6 

11 




- 6 




- 6 




+ i 




4 1 

10 




- S 


. 


- 3 




4- 1 




4 1 

9 




+ 3 




+ 3 




+ 2 




4 - 2 

8 




+ 3 




+ 6 




+ 5 




4 5 

7 




+ 4 




+ 4 




+ 5 




4 5 

6 




+ 2 




+ 2 




+ 4 




4 A 

5 




0 




0 




4 1 




4 1 

4 




+ 3 




+ 3 




+ s 




4 3 

3 




+ 5 




4- 5 




4 4 




4 A 

2 




+ 5 




+ 5 




+ 5 




4 5 

1 




+ 1 



+ 1 

+ 1 




+ / 




+ i 
















Total.. 




+ 879 




+414 




+738 




-742 







































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


47 


Mean elevations and. corrections for topography and isostatic compensation , separate zones, for selected stations in Europe — 

Continued. 


Zone 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com¬ 

pensa¬ 

tion 

Eleva¬ 
tion in 
feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

com- 

pensa- 

tion 

Chaumont, Switzerland 

, No. 9 

Neuenburg. Switzerland (Neu- 
chatel) No. 10 

Gornergrat, Switzerland 

, No. 11 

Riflelberg, Switzerland, 

No. 12 

A 

3340 

+ 2 

0 

+ 2 

1600 

+ 2 

0 

+ 21 


+ 2 

0 

+ 2 

8420 

+ 2 

0 

+ 2 

B 

3350 

+ 58 

0 

+ 58 

1570 

+ 61 

0 

+ 61 


+ 63 

- 4 

+ 64 

8400 

+ 60 

0 

+ 60 

C 

3330 

+ 146 

0 

+ 146 

1540 

+122 

0 

+ 122 


+ 164 

- 4 

+160 

8340 

+156 

- 4 

+ 152 

D 

3270 

+241 

- 5 

+236 

1530 

+ 148 

0 

+ 148 


+323 

- 12 

+311 

8280 

+326 

- 9 

+317 

E 

3080 

+243 

- 8 

+235 

1640 

+ 86 

- 2 

+ 84 


+504 

- 17 

+487 

8100 

+480 

- 16 

+464 

F 

2580 

+144 

- 8 

+136 

1810 

+ 33 

- 4 

+ 34 


+538 

- 30 

+508 

7590 

+457 

- 23 

+434 

G 

2180 

+ 64 

- 8 

+ 56 

1970 

+ 16 

- 6 

+ 10 


+402 

- 31 

+371 

7980 

+336 

- 30 

+306 

H 

2060 

+ 35 

- 15 

+ 20 

1840 

+ 11 , 

- 12 

- 1 


+333 

- 44 

+289 

8660 

+269 

- 45 

+224 

I 

2310 

+ 40 

- 22 

+ 18 

1960 

+ 7 

- 17 

- 10 


+306 

- 94 

+212 

9940 

+216 

- 88 

+128 

J 

2540 

+ 22 

- 30 

- 8 

2430 

+ 5 

- 27 

- 22 


+180 

-107 

+ 73 

10 390 

+121 

-108 

+ 13 

K 

2510 

+ 14 

- 36 

- 22 

2480 

- 10 

- 35 

— 45 


+ 137 

-146 

- 9 

8730 

+105 

-146 

- 41 

L 

2500 

4- i 

- 61 

- 60 

2520 

+ 2 

- 63 

- 61 


+ 80 

-177 

- 97 

7410 

+ 65 

-175 

-110 

M 

2760 

+ 6 

-162 

-156 

2760 

+ 2 

-162 

-160 


+ 82 

-328 

-246 

5770 

+ 63 

-339 

-276 

N 

3120 

+ 10 

-170 

-160 

3120 

+ 4 

-166 

-162 


+ 26 

-243 

-217 

4550 

+ 25 

-244 

-219 

0 

2960 

0 

-150 

-150 

2960 

0 

-150 

-1.50 


+ 2 

-162 

-160 

2920 

0 

-142 

-142 

18 




— 24 




- 24 




32 




32 

17 




- 24 




- 24 




— 31 




— 31 

16 




- 22 




- 22 




23 




— 23 

15 




- 20 




- 20 




17 




17 

14 




- 21 




- 21 




11 




u 

13 




- 23 




- 23 




— 11 




— 11 

12 




- 6 




- 6 




— 6 




— 6 

11 




+ 4 




+ 4 




4- 3 




4- 3 

10 




+ 2 




4- 3 




— l 




_ i 

9 




+ 1 




+ i 




H- 3 




+ 3 

8 




+ 5 




+ s 




+ 8 




4- 8 

7 




+ 6 




+ 5 




-f 5 




4- 5 

6 




+ 4 




+ 4 




4- A 




4- A 

5 




+ 1 




+ l 








4- 1 

4 




+ 3 




+ 3 




4- 3 




4 . 3 

3 




+ 4 




+ 4 




+ A 




4- A 

2 




+ 5 




+ 5 




+ 5 




+ 5 

1 




+ 1 




+ 1 




+ i 




+ i 














Total.. 




+246 




—255 




+ 1653 




+ 1217 
















Zermatt, Switzerland, 

No. 13 

Belalp, Switzerland, No. 14 

Brig, Switzerland, No. 15 

Eggishorn, Switzerland, 

No. 16 

A 

5260 

+ 2 

0 

+ 2 

6995 

+ 2 

0 

+ 2 

2240 

+ 2 

0 

+ 2 

7180 

+ 2 

0 

+ 2 

B 

5260 

+ 68 

0 

+ 68 

6900 

+ 52 

0 

+ 52 

2250 

+ 64 

0 

+ 64 

7130 

+ 54 

0 

+ 54 

C 

5280 

+ 164 

- 4 

+ 160 

6770 

+ 142 

- 4 

+ 133 

2270 

+ 139 

0 

+ 139 

7010 

+145 

- 4 

+141 

D 

5480 

+296 

- 6 

+290 

6530 

+289 

- 6 

+283 

2440 

+ 189 

0 

+ 189 

6900 

+293 

- 6 

+287 

E 

6230 

+346 

- 14 

+332 

6310 

+421 

- 13 

+408 

2680 

+ 149 

- 8 

+ 141 

6990 

+442 

- 15 

+427 

F 

7044 

+233 

- 21 

+212 

6.530 

+388 

- 20 

+368 

3070 

+ 72 

- 10 

+ 62 

6590 

+371 

- 20 

+351 

G 

7910 

+ 116 

- 28 

+ 88 

6710 

+262 

- 25 

+237 

4030 

+ 17 

- 14 

+ 3 

6070 

+247 

- 20 

+227 

H 

8700 

+ 60 

- 43 

+ 17 

6810 

+ 175 

- 32 

+ 143 

5100 

- 24 

- 25 

- 49 

6240 

+ 190 

- 31 

+ 159 

I 

9380 

+ 25 

- 81 

— 56 

6990 

+ 137 

- 60 

+ 77 

6250 

- 56 

- 52 

-108 

7120 

+ 162 

- 62 

+ 100 

J 

10 500 

+ 6 

-111 

-105 

6990 

+ 86 

- 74 

+ 12 

6900 

- 34 

- 75 

-109 

8030 

+ 84 

- 86 

- 2 

K 

8860 

+ 25 

-149 

-124 

7480 

+ 68 

-125 

- 57 

7170 

- 33 

-119 

-152 

S140 

+ 68 

-136 

- 68 

L 

7720 

+ 19 

-182 

-163 

6900 

+ 51 

-162 

-111 

7290 

- 29 

-169 

-198 

6210 

+ 45 

-140 

- 95 

M 

6220 

+ 22 

-343 

-321 

5820 

+ 40 

-340 

-300 

5860 

- 15 

-343 

-358 

5370 

+ 45 

-317 

-272 

N 

4770 

+ 9 

-246 

-237 

42.50 

+ 24 

-230 

-206 

4250 

+ 8 

-226 

-218 

4060 

+ 20 

-218 

-198 

O 

2920 

0 

-142 

-142 

3210 

0 

-157 

-157 

3210 

0 

-157 

-157 

3330 

0 

-159 

-159 

18 




— 32 




- 26 




— 26 




- 26 

17 




- 31 




- 25 




- 25 




- 26 

16 




— 23 




- 22 




— 22 




- 22 

15 




- 17 




- 20 




— 20 




- 20 

14 




- 11 




- 14 




- 14 




- 14 

18 




- 11 




- 16 




— 16 




- 16 

12 




— 6 




- 7 




- 7 




- 7 

11 




+ 3 




+ 1 




+ 1 




+ 1 

10 




- i 




+ 1 




+ 1 




4- 1 

9 




+ 3 




+ 1 




+ 1 




+ i 

g 




+ 8 




+ 6 




+ 6 




+ 6 

7 




+ 6 




+ 5 




+ 5 




+ 5 

6 




+ 4 




+ 4 




+ 4 




+ 4 

5 




+ i 




+ i 




+ i 




+ i 

4 




4- 3 




+ 3 




+ 3 




+ s 

3 




+ 4 




+ 4 




+ 4 




+ 4 

2 




+ 5 




+ 5 




+ 5 




+ 6 

i 




+ 1 




+ 1 




+ 1 




+ 1 




















— 74 




+791 




-847 




+856 




















































































































































































































































48 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Mean elevations and corrections for topography and isostatic compensation, separate zones, for selected stations in Europe —Con. 


Zone 

Eleva¬ 
tion 
in feet 

Topog¬ 

raphy 

Com¬ 

pensa¬ 

tion 

Topog¬ 

raphy 

and 

compen¬ 

sation 

Fiesch, Switzerland, No. 17. 

A 

3440 

+ 2 

0 

+ 2 

B 

3510 

+ 50 

0 

+ 50 

c 

3510 

+ 153 

0 

+153 

D 

3640 

+253 

- 6 

+247 

E 

4020 

+248 

- 8 

+240 

F 

4640 

+ 132 

- 13 

+119 

G 

5220 

+ 55 

- 18 

+ 37 

H 

6070 

+ 12 

- 32 

- 20 

I 

6850 

- 8 

- 58 

- 66 

J 

8020 

- 16 

- 85 

-101 

K 

7920 

- 20 

-132 

-152 

L 

6370 

+ 5 

-149 

-144 

M 

5370 

- 4 

-318 

-322 

N 

4060 

+ 7 

-221 

-214 

0 

3330 

0 

-159 

-159 

18 




- 26 

17 




- 25 

16 




- es 

15 




— 20 

14 




- u 

13 




- 16 

12 




- 7 

11 




+ 1 

10 




+ 1 

9 




+ 1 

8 




+ 6 

7 




+ 5 

6 




+ 4 

5 




+ i 

4 




+ 3 

3 




+ 4 

2 




+ 6 

1 




+ 1 






Total.... 




-428 







PRINCIPAL FACTS FOR 219 STATIONS IN THE UNITED STATES. 

The names of the observers, with the dates on which the observations were made, are given 
with the summaries of observations at the gravity stations, on pages 144 to 176. 

Since the preceding report on gravity investigations (Special Publication No. 12, 1912) 94 
stations have been established in the United States. At all of these stations the Mendenhall 
half-second pendulums were used. A description of the apparatus and of the method of 
determining the period of the pendulums is given in Appendix 5, Report for 1901, by G. R. 
Putnam, and in Appendix 1, Report for 1894. Since 1909 the flexure of the pendulum 
case and pier has been determined by means of the interferometer, designed and made by 
E. G. Fischer, chief of the instrument section of the United States Coast and Geodetic Survey. 
This instrument and its use are described by W. H. Burger in Appendix 6 of the Report for 
1910. 

Previous to 1913 the chronometer rates were determined by local observations on the 
stars with a portable astronomical transit. Since that date the rates of the chronometers have 
been determined from time transmitted by noon signals sent from the Naval Observatory at 
Washington over the wires of the Western Union Telegraph Company and the Postal Tele¬ 
graph Company. As only the rates were required, and not the chronometer corrections, the 
effect of transmission time was eliminated, as it proved to be nearly the same for each day at 
any one station. Before making use of the Naval Observatory time it was carefully tested at 
the base station at the Survey office. It was also tested on the field by reoccupying four 
stations. The tests proved entirely satisfactory, as the results agreed closely with those 
previously obtained when the chronometers were rated by star observations. 

An improvement was made by having a thick felt-and-leather cover for the pendulum case. 
This made the temperature in the case much more uniform, and no doubt added to the accuracy 
of the results. This covering is shown in figures 3 and 4. 
































Special Publication No. 40. 



FIG. 1.—ORIGINAL FORM OF THE MENDENHALL HALF-SECOND PENDULUM APPARATUS. 















Special Publication No. 40. 




FIG. 2.—MENDENHALL HALF-SECOND PENDULUMS AS ORIGINALLY CONSTRUCTED WITH KNIFE-EDGE ATTACHED 

TO HEAD OF PENDULUM AND DIVIDED INTO TWO PARTS. 














Special Publication No. 40. 



FIG. 3.—PRESENT PENDULUM APPARATUS SHOWING VERTICAL FORM OF TELESCOPE, ELECTRIC ILLUMINATION 
FOR OBSERVING SLIT, AND THE FELT-AN D-LEATHER CASE FOR CONTROLLING THE TEMPERATURE. 










Special Publication No. 40. 



FIG. 4.—FELT-AND-LEATHER CASE FOR TEMPERATURE CONTROL PARTLY REMOVED FROM PENDULUM RECEIVER 









INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


49 


Another improvement was made by changing the telescope of the flash apparatus to the 
vertical instead of the horizontal position, as formerly, by the use of a prism. (See fig. 3.) 
With the telescope vertical the observer is able to work with greater comfort, as the case is 
always mounted only a few inches above the floor of the room in which observations are made. 

During the work at the 94 recent stations, only one of the six pendulums used gave trouble. 
This was pendulum No. B4. The trouble was eliminated by strengthening the connection 
between the stem and bob by an additional rivet. 

In most cases three pendulums were used at each station. Each pendulum was swung 
for three periods of approximately eight hours each between two consecutive noon time-signals. 
The exceptions to this general rule occurred when in Mr. Powell’s work on the field in the spring 
of 1915 pendulum No. B4 showed great irregularities. He continued that season with the other 
two pendulums of the set. He swung one of the pendulums for two days, or six periods of eight 
hours each, and the other for three such periods, making nine periods in all, the number ordi¬ 
narily obtained when using three pendulums. 

The pendulums were standardized at the Coast and Geodetic Survey office at Washington 
between each two seasons. The results of the standardizations are given on page 141. 

Complete computations have been made for 219 gravity stations in the United States by 
three methods of reduction and the results are shown in the following table. 

The theoretical value in dynes of gravity at sea level was computed by Helmert’s formula 
of 1901 for the Potsdam system, namely: 

Yo = 978.030 (1 + 0.005302 sin 2 0-0.000007 sin 2 20) 

% 

The correction in dynes for elevation of station was computed by the formula — 0.000308627, 
in which H is the elevation in meters. It should be carefully noted that with the sign as 
given this is the reduction from sea level to the station, a correction to the theoretical value not to 
the observed value. This correction takes account of the increased distance of the station from 
the attracting mass, as if the station were in the air and there were no irregularities in the 
earth’s surface (or topography). 

The corrections for topography and compensation by the Hayford method were com¬ 
puted with the reduction tables shown on pages 30 to 47 of Special Publication No. 10, and 
the resultant effect was applied as a correction to the theoretical value at sea level. 

These corrections are often applied to the observed values and the results are compared 
with the theoretical value of gravity at sea level. The method employed in this publication 
and in Special Publications Nos. 10 and 12 appears to be the more logical one. 

The computed value of gravity, g c , at the station is the theoretical value of gravity at sea 
level, 7 0 , corrected for elevation and for topography and compensation. It is therefore directly 
comparable with g, the observed value of gravity at the station. The column g-g c , therefore, 
represents the departures of the observed values from computed values based upon the Hehnert 
formula of 1901, upon the usual reduction for elevation, and upon the Hayford reductions that 
take account of topography and compensation. 

All observed values, g, in the following table depend upon relative determinations with the 
half-second pendulums and are based on 980.112 dynes as the value of gravity at the Coast 
and Geodetic Survey office at Washington. This value depends upon the absolute determina¬ 
tion of the value of gravity at Potsdam,® Germany, and upon the adjustment of the net of base 
stations throughout the world. (See pp. 25 and 244 of third volume, by Dr. E. Borrass in 
1911, of the Report of the Sixteenth General Conference of the International Geodetic Associ¬ 
ation at London and Cambridge in 1909.) The observations used in the adjustment to con¬ 
nect Washington with stations in Europe were made by G. R. Putnam in 1900. 6 

a Bestimmung der absoluten Grosse der Schwerkraft zu Potsdam mit Reversionspendeln, von Prof. F. ICiihnen und Prof. Dr. Ph. Furtwangler, 
p. 380. 

b Determination of Relative Value of Gravity in Europe and the United States in 1900, G. R. Putnam, Appendix 5, Coast and Geodetic Survey 
Report, 1901, pp. 354-355. 

59387°—17-4 




50 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 
Principal facts for 219 gravity stations in the United States. 


Number and name of station 

Latitude 

<t> 

Longitude 

X 

Eleva¬ 

tion 

H 

Theo¬ 

retical 

gravity 

■Yo 

Correc¬ 
tion for 
eleva¬ 
tion 

Correc¬ 
tion for 
topogra¬ 
phy and 
compen¬ 
sation 

Com¬ 
puted 
gravity 
at sta¬ 
tion 

9o 

Observed 
gravity 
at sta¬ 
tion 

9 

9-9c 


O 

t 

o 

/ 

Meters 

Dynes. 

Dynes. 

Dynes. 

Dynes. 

Dynes. 

Dynes. 

1. Key West, Fla. 

24 

33.6 

81 

48.4 

1 

978.922 

0.000 

+0.035 

978.957 

978.970 

+0.013 

2. West Palm Beach, Fla. 

26 

42.8 

SO 

02.8 

2 

979.073 

- .001 

+ .031 

979.103 

979.129 

+ .026 

3. Punta Gorda, Fla. 

26 

56.2 

82 

03 

1 

979.089 

.000 

+ .020 

979.109 

979.127 

+ .018 

4. Apalachicola, Fla. 

29 

43.5 

84 

58.8 

4 

979.300 

- .001 

+ .015 

979.314 

979.322 

+ .008 

5. New Orleans, La. 

29 

57.0 

90 

04.2 

2 

979.317 

- .001 

+ .013 

979.329 

979.324 

- .005 

6 . Rayville, La. 

32 

28 

91 

45 

26 

979.519 

- .008 

+ .008 

979. 519 

979.543 

+ .024 

7. Galveston, Tex. 

29 

18.2 

94 

47.5 

3 

979.267 

- .001 

+ .007 

979.273 

979.272 

- .001 

8 . Point Isabel, Tex. 

26 

04.7 

97 

12.4 

8 

979.028 

- .002 

+ .015 

979.041 

979.076 

+ .035 

9. Laredo, Tex'.. 

27 

30.5 

99 

31.2 

129 

979.131 

- .040 

+ .003 

979.094 

979.082 

- .012 

10. Austin, Tex. (capitol). 

30 

16.5 

97 

44.3 

170 

979.343 

- .052 

- .003 

979.288 

979.288 

.000 

11. Austin, Tex. (university). 

30 

17.2 

97 

44.2 

189 

979.344 

- .058 

- .001 

979.285 

979.283 

- .002 

12. McAlester, Okla. 

34 

56.2 

95 

46.2 

240 

979.725 

- .074 

+ .001 

979. 652 

979. 633 

- .019 

13. Little Rock, Ark. 

34 

45.0 

92 

16.4 

89 

979. 709 

- .027 

+ .001 

979. 683 

979.721 

+ .038 

14. Columbia, Tenn. 

35 

36.7 

87 

02.5 

207 

979.783 

— .064 

4- .006 

979.725 

979. 759 

+ .034 

15. Atlanta, Ga. 

33 

45.0 

84 

23.3 

324 

979.625 

- .100 

+ .014 

979.539 

979.524 

- .015 

16. McCormick, S. C. 

33 

54.8 

82 

18.0 

163 

979. 639 

- .050 

+ .012 

979.601 

979.624 

+ .023 

17. Charleston, S. C. 

32 

47.2 

79 

56.0 

6 

979. 545 

- .002 

+ .016 

979.559 

979.546 

- .013 

18. Beaufort, N. C. 

34 

43.1 

76 

39. S 

1 

979. 706 

.000 

4- .036 

979. 742 

979. 729 

- .013 

19. Charlottesville, Va. 

38 

02.0 

78 

30.3 

166 

979.992 

- .051 

+ .002 

979.943 

979.938 

- .005 

20. Deer Park, Md. 

39 

25.0 

79 

19.8 

770 

980.114 

- .238 

+ .041 

979.917 

979.935 

+ .018 

21. Washington. D. C. (Coast and Geodetic Sur- 









980.067 

980.112 

+ .045 

vey Office). 

38 

53.2 

77 

00.5 

14 

980.067 

- .004 

+ .004 

22. Washington, D. C. (Smithsonian Institution). 

38 

53.3 

77 

01.5 

10 

980.067 

— .003 

4- .003 

980.067 

980.114 

+ .047 

23. Baltimore, Md. 

39 

17.8 

76 

37.3 

30 

9S0.103 

- .009 

4- .006 

980.100 

980.097 

- .003 

24. Philadelphia, Pa. 

39 

57.1 

75 

11.7 

16 

980.162 

- .005 

4- .009 

9S0.166 

980.196 

+ .030 

25. Princeton, N. J. 

40 

21.0 

74 

39.5 

64 

980.196 

- .020 

4- .013 

980.189 

980.178 

- .011 

26. Hoboken, N. J. 

40 

44 

74 

02 

11 

980.232 

- .003 

4- .008 

980.237 

980.269 

+ .032 

27. New York, N. Y. 

40 

48.5 

73 

57.7 

38 

980.238 

- .012 

4- .011 

980.237 

980.267 

+ .030 

28. Worcester, Mass. 

42 

16.5 

71 

48.5 

170 

980.370 

- .052 

4- .018 

980.336 

980.324 

— .012 

29. Boston, Mass. 

42 

21.6 

71 

03.8 

22 

980.377 

- .007 

4- .013 

9S0.383 

980.396 

+ .013 

30. Cambridge, Mass. 

42 

22.8 

71 

07.8 

14 

980.379 

- .004 

4- .010 

980.385 

980.398 

+ .013 

31. Calais, Me. 

45 

11.2 

67 

16.9 

38 

980.633 

- .012 

4- .010 

980.631 

980.631 

.000 

32. Ithaca, N. Y. 

42 

27.1 

76 

29.0 

247 

980.3S6 

- .076 

4- .005 

980.315 

980.300 

- .015 

33. Cleveland, Ohio. 

41 

30.4 

81 

36.6 

210 

980.301 

- .065 

.000 

980.236 

980.241 

+ .005 

34. Cincinnati, Ohio. 

39 

08.3 

84 

25.3 

245 

980.089 

- .076 

4 - .002 

980.015 

980.004 

- .011 

35. Terre Haute, Ind. 

39 

28.7 

87 

23.8 

151 

980.119 

- .047 

4- .001 

980.073 

980.072 

- .001 

36. Chicago, Ill. 

41 

47.4 

87 

36.1 

182 

980.326 

- .056 

4- .007 

980.277 

980.278 

+ .001 

37. Madison, Wis. 

43 

04.6 

89 

24.0 

270 

980. 442 

- .083 

4- .003 

980.362 

980.365 

+ .003 

38. St. Louis, Mo. 

38 

38.0 

90 

12.2 

154 

980.045 

- .048 

4- .001 

979.998 

980.001 

+ .003 

39. Kansas City, Mo. 

39 

05.8 

94 

35.4 

278 

980.085 

- .086 

- .001 

979.998 

979.990 

- .008 

40. Ellsworth, Kans. 

38 

43.7 

98 

13.5 

469 

980.053 

- .145 

- .004 

979.904 

979.926 

4 - .022 

41. Wallace, Kans. 

38 

54.7 

101 

35.4 

1005 

980.069 

- .310 

.000 

979.759 

979. 755 

- .004 

42. Colorado Springs, Colo. 

38 

50.7 

104 

49.0 

1841 

980.064 

- .568 

- .007 

979.489 

979.490 

+ .001 

43. Pikes Peak, Colo. 

38 

50.3 

105 

02.0 

4293 

980.063 

-1.325 

4- .187 

978.925 

978.954 

+ .029 

44. Denver, Colo. 

39 

40.6 

104 

56.9 

1638 

980.137 

- .505 

- .015 

979. 617 

979. 609 

- .008 

45. Gunnison, Colo. 

38 

32.6 

106 

56.0 

2340 

980.037 

- .722 

- .001 

979.314 

979.342 

+ .028 

46. Grand Junction. Colo. 

39 

04.2 

108 

33.9 

1398 

980.083 

- .431 

- .051 

979.601 

979.633 

+ .032 

47. Green River, Utah. 

3S 

59.4 

110 

09.9 

1243 

980.076 

- .384 

- .043 

979.649 

979.636 

- .013 

48. Pleasant Valley Junction, Utah. 

39 

50.8 

111 

00.8 

2191 

980.152 

- .676 

4- .024 

979.500 

979.512 

+ .012 

49. Salt Lake City, Utah. 

40 

46.1 

111 

53.8 

1322 

9S0.234 

- .408 

- .041 

979.785 

979.803 

4- .018 

50. Grand Canyon, Wyo. 

44 

43.3 

110 

29.7 

2386 

980.591 

- .736 

4- .038 

979.893 

979.899 

+ .006 

51. Norris Geyser Basin, Wyo. 

44 

44.2 

110 

42.0 

2276 

980.592 

- .702 

4- .031 

979.921 

979.950 

4- .029 

52. Lower Geyser Basin, Wyo. 

44 

33.4 

110 

48.1 

2200 

930.576 

- .679 

4 - .028 

979.925 

979.932 

4- .007 

53. Seattle, Wash, (university). 

47 

39.6 

122 

18.3 

58 

980- 856 

- .018 

- .020 

980.818 

980.733 

- .085 

54. San Francisco, Cal. 

37 

47.5 

122 

25.7 

114 

979.970 

- .035 

4- .045 

979.980 

979.965 

- .015 

Mount, Hamilton, Cal_ _. 

37 

20.4 

121 

38.6 

1282 

979.931 

— .396 

4- .120 

979.655 

979.660 

980.725 

4- .005 

- .085 

56. Seattle, Wash, (high school). 

57- Tron River, Mieh. 

47 

36.5 

122 

19.8 

74 

980.851 

- .023 

- .018 

980.810 

46 

05. 4 

88 

38. 4 

458 

980.714 

— .141 

4- .014 
4- .008 

980.587 

980.633 
980. 771 
980.917 

4- .046 
+ .031 


47 

48.6 

92 

01.0 

44S 

980.870 

— .138 

980.740 
980.890 

59. Pembina, N. Dak. 

48 

58.1 

97 

14.9 

243 

980.974 

— .075 

— .009 

+ .027 

60. Mitchell, S. Dak. 

43 

41.8 

98 

01.8 

408 

980.498 

- .126 

— .006 

980.366 

9S0.375 

979.305 
979.221 

+ .009 

- .021 

61. Sweetwater, Tex. 

32 

28.4 

100 

24.1 

655 

979.519 

— .202 

4- .009 

979.326 

62. Kerrvilie, Tex. 

30 

01.3 

99 

07.6 

498 

979.323 

— .154 

4- .013 
4- .001 

979.182 

+ . 039 
+ .015 

63. El Paso, Tex. 

31 

46.3 

106 

29.0 

1146 

979. 462 

— .354 

979.109 

979.124 

64. Nogales, Ariz. 

31 

21.3 

110 

56.6 

1181 

979.429 

— .364 

4- .038 
— .010 

979.103 

979.061 

— .042 

65. Yuma, Ariz. 

32 

43.3 

114 

37.0 

54 

979.539 

- .017 

979.512 

979.529 

4 - .017 

- .042 

66 . Compton, Cal. 

33 

53.4 

118 

13.2 

20 

979.636 

- .006 

.000 

979. 630 

979.5S8 

67. Goldfield, Nev. 

37 

42.2 

117 

14.5 

1716 

979.963 

— .529 

4- .027 

979. 461 

979. 456 

- .001 
+ .001 
- .002 
- .001 

68 . Yavapai, Ariz.. 

36 

03.9 

112 

07.1 

2179 

979.821 

— .672 

4- .034 

979.183 

979.192 

69. Grand Canyon, Ariz. 

36 

05.3 

112 

06.8 

849 

979.823 

— .262 

— .096 

979.465 

979.463 

70. Gallup, N/Mex . 

35 

31.8 

108 

44.2 

1990 

979.775 

- .614 

4- .014 

979.175 

979.170 

71. Las Vegas, N. Mex. 

35 

35.8 

105 

12.1 

1960 

979.781 

— .605 

4- .017 

979.193 

979.204 
979.577 
979.566 
980.597 

4- .011 
4- . 04( 
+ .011 
+ .06' 

72. Shamrock, Tex. 

35 

12.8 

100 

11. 4 

708 

979.748 

- .218 

4- .007 
- .001 

- .005 

979.537 

73. Denison, Tex . 

33 

45.3 

96 

32.8 

230 

979.625 

— .071 

979.553 
980.530 

74. Minneapolis, Minn. 

75. Lead, S. Dak. 

44 

58.7 

93 

13.9 

256 

980.614 

- .079 

44 

21.1 

103 

45.6 

1590 

980.557 

- .491 

4- .044 

980.110 

980.170 

+ . 06( 











































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


51 


Principal facts for 219 gravity stations in the United States —Continued. 


Number and name of station 

Latitude 

<t> 

Longitude 

X 

Eleva¬ 

tion 

H 

Theo¬ 

retical 

gravity 

7o 

Correc¬ 
tion for 
eleva¬ 
tion 

Correc¬ 
tion for 
topogra¬ 
phy and 
compen¬ 
sation 

Com¬ 
puted 
gravity 
at sta¬ 
tion 

9 o 

Observed 
gravity 
at sta¬ 
tion 

9 

9~9o 


o 

/ 

o 

/ 

Meters 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

76. Bismarck, N. Dak. 

46 

48.5 

100 

47.0 

516 

9S0. 779 

-0.159 

-0.005 

980.615 

980.625 

+ 0.010 

77. Hinsdale, Mont. 

48 

23.8 

107 

05.3 

661 

980.923 

- .204 

- .017 

980.702 

980. 739 

+ .037 

78. Sandpoirit, Idaho. 

48 

16.4 

116 

33.3 

637 

980.911 

- .197 

- .044 

980.670 

980. 6S0 

-t- .010 

79. Boise, Idaho. 

43 

37.2 

116 

12.3 

821 

980.491 

- .253 

- .042 

980.196 

980.212 

4- .016 

80. Astoria, Oreg. 

46 

11.3 

123 

50.2 

1 

980.724 

.000 

4- .008 

980.732 

980.727 

- .005 

81. Sisson, Cal. 

41 

18.3 

122 

19.6 

1048 

980.282 

- .323 

4- .015 

979.974 

979.972 

- .002 

82. Rock Springs, Wyo. 

41 

35.1 

109 

13.2 

1910 

980.308 

- .589 

- .001 

979.718 

979.739 

-f .0 21 

83. Paxton, Nebr. 

41 

07.4 

101 

21.3 

932 

980.266 

- .288 

4 - .002 

979.980 

979.982 

4 - .002 

84. Washington, D. C. (Bureau of Standards)... 

38 

56.3 

77 

04.0 

103 

980.070 

- .032 

4 - .012 

980.050 

980.095 

+ .045 

85. North Hero, Vt. 

44 

49.1 

73 

17.5 

35 

980.599 

- .011 

- .009 

980.579 

980.588 

+ .009 

86 . Lake Placid, N. Y. 

44 

17.5 

73 

59.1 

571 

980.551 

- .176 

4 - .032 

980.407 

980.421 

+ .014 

87. Potsdam, N. Y. 

44 

40.1 

74 

58.8 

130 

980.586 

- .040 

- .004 

980.542 

980.571 

+ .029 

88 . Wilson, N. Y. 

43 

18.4 

78 

49.6 

87 

980.462 

- .027 

- .002 

980.433 

980.431 

- .002 

89. Alpena, Mich. 

45 

03.8 

83 

27.0 

178 

980.622 

- .055 

.000 

980.567 

980.555 

- .012 

90. Virginia Beach, Va. 

36 

50.5 

75 

58.4 

4 

979.888 

- .001 

+ .025 

979.912 

979.872 

- .040 

91. Durham, N. C. 

36 

00.2 

78 

53.5 

126 

979.816 

- .039 

+ .014 

979.791 

979.835 

4- .044 

92. Fernandina, Fla.. 

30 

40.2 

81 

27.7 

3 

979.374 

- .001 

+ .017 

979.390 

979.408 

4 - .018 

93. Wilmer, Ala. 

30 

49.2 

88 

20.5 

69 

979.386 

- .021 

4- .018 

979.383 

979.347 

- .036 

94. Aliceville, Ala. 

33 

07.6 

88 

10.8 

61 

979.572 

- .019 

4- .008 

979.561 

979.552 

- .009 

95. New Madrid, Mo. 

36 

35.5 

89 

31.6 

79 

979.867 

- .024 

+ .001 

979.844 

979.853 

+ .009 

96. Mena, Ark. 

34 

35.2 

94 

14.6 

368 

979.695 

- .114 

4- .015 

979.596 

979.552 

- .044 

97. Nacogdoches, Tex. 

31 

36.2 

94 

37.8 

92 

979.448 

- .028 

4 - .008 

979.427 

979.424 

- .004 

98. Alpine, Tex. 

30 

21.5 

103 

39. 7 

1359 

979.349 

- .420 

4- .033 

978.962 

978.991 

+ .029 

99. Farwell, Tex. 

34 

23.2 

103 

01.8 

1259 

979. 678 

- .388 

4- .011 

979.301 

979.293 

- .008 

100. Guymon, Okla. 

36 

40.7 

101 

28.7 

949 

979.874 

- .293 

- .001 

979.580 

979.571 

- .009 

101 . Helenwood, Tenn. 

36 

25.9 

84 

32.6 

422 

979.853 

- .130 

+ .015 

979.738 

979.786 

+ .048 

102. Cloudland, Tenn. 

36 

06.2 

82 

07.9 

1890 

979.824 

- .583 

4- .130 

979.371 

979.383 

4 - .012 

103. Hughes, Tenn. 

36 

08.5 

82 

07.2 

994 

979.827 

- .306 

4- .053 

979.574 

979.553 

- .021 

104. Charleston, W. Va. 

38 

20.9 

81 

37.7 

184 

980.019 

-•.057 

- .010 

979.952 

979.936 

- .016 

105. State College, Pa. 

40 

47.9 

77 

51.8 

358 

980.237 

- .110 

4 - .010 

980.137 

980.124 

- .013 

106. Fort Kent, Me. 

47 

14.9 

68 

36.0 

160 

980.818 

- .049 

4- .001 

980.770 

980.765 

- .005 

107. Prentice, Wis. 

45 

32.6 

90 

17.8 

469 

980.665 

- .145 

4 - .010 

980.530 

980.562 

4- .032 

108. Fergus Falls, Minn. 

46 

17.2 

96 

05.0 

366 

980. 732 

- .113 

4 - .001 

980.620 

980.622 

4- .002 

109. Sheridan, Wyo. 

44 

48.0 

106 

58.7 

1150 

980.598 

- .355 

- .031 

980.212 

980.252 

+ .040 

110. Boulder, Mont. 

46 

14.2 

112 

07.3 

1493 

980.727 

- .461 

- .007 

980.259 

980.252 

- .007 

111. Skykomish. Wash. 

47 

42.4 

121 

22.3 

280 

980.860 

- .086 

- .047 

980.727 

980.707 

- .020 

112. Olympia, Wash. 

47 

03.4 

122 

52.7 

19 

980.802 

- .006 

- .012 

980.784 

980.825 

4- .041 

113. Heppner, Oreg. 

45 

21.4 

119 

33.2 

598 

980.648 

- .185 

- .007 

980.456 

980.437 

- .019 

114. Truckee, Cal. 

39 

19.6 

120 

11.4 

1805 

980.105 

- .557 

+ .057 

979.605 

979.585 

- .020 

115. Winnemucca, Nev. 

40 

58.4 

117 

43.8 

1311 

980.253 

- .404 

- .004 

979.845 

979.844 

- .001 

116. Ely, Nev. 

39 

14.9 

114 

53.4 

1962 

980.099 

- .605 

+ .020 

979.514 

979.501 

- .013 

117. Guernsey, Wyo. 

42 

16.1 

104 

44.0 

1322 

980.369 

- .408 

- .016 

979.945 

979.989 

4- .044 

118. Pierre, S. Dak. 

44 

21.9 

100 

20.8 

454 

9S0.558 

- . 140 

- .013 

980.405 

980.427 

4- .022 

119. Fort Dodge, Iowa. 

42 

30.8 

94 

11.4 

340 

980.391 

- .105 

+ .002 

980.288 

980.311 

4- .023 

120. Keithsburg, Ill. 

41 

06.4 

90 

57 

167 

980.265 

- .051 

- .003 

980.211 

980.211 

000 

121. Grand Rapids, Mich. 

42 

58.0 

85 

40.8 

236 

980.432 

- .073 

+ .003 

980.362 

980.372 

4 - .010 

122. Angola, Ind. 

41 

37.7 

85 

00.6 

318 

980.312 

- .098 

+ .011 

980.225 

980.244 

4- .019 

123. Albany, N. Y. 

42 

39.1 

73 

46.1 

61 

980.404 

- .019 

- .006 

980. 379 

980. 344 

- .035 

124. Port Jervis, N. Y. 

41 

22.4 

74 

41.1 

141 

980.288 

- .044 

4- .003 

980.247 

980.222 

- .025 

125. Atlantic City, N. J. 

39 

21.9 

74 

25.0 

3 

980.110 

- .001 

+ .018 

980.127 

980.112 

- .015 

126. Bridgehampton, N. Y. 

40 

56.0 

72 

18.4 

10 

980.249 

- .003 

4 - .020 

980.266 

980.252 

- .014 

127. Chatham, Mass. 

41 

40.7 

69 

57.3 

2 

980.316 

- .001 

4- .024 

980.339 

980.333 

- .006 

128. Rockland, Me. 

44 

06.3 

69 

06.9 

9 

980.535 

- .003 

4- .011 

980.543 

980.536 

- .007 

129. Lancaster, N. H. 

44 

29.5 

71 

34.3 

261 

980.570 

- .081 

4- .007 

980.496 

980.486 

- .010 

130. Whitehall, N. Y. 

43 

33.0 

73 

23.8 

38 

980.484 

- .012 

- .012 

980.460 

980.429 

- .031 

131. Little Falls, N. Y. 

43 

02.7 

74 

51.2 

137 

980.439 

- .042 

- .007 

980.390 

980.374 

- .016 

132. Watertown, N. Y. 

43 

58.3 

75 

54.6 

147 

980.522 

- .045 

+ .001 

980.478 

980.461 

- .017 

133. Southport, N. Y. 

42 

03.7 

76 

48.6 

266 

980.351 

- .082 

4- .004 

980.273 

980.251 

- .022 

134. Erie, Pa.... 

42 

07.8 

80 

01.8 

198 

980.357 

- .061 

4 - .001 

980.297 

980.278 

- .019 

135. Parkersburg, W. Va. 

39 

16.0 

81 

33.7 

185 

980.101 

- .057 

- .006 

980.038 

980.022 

- .016 

136. Columbus, Ohio. 

39 

57.8 

82 

59.4 

231 

980.163 

- .071 

+ .001 

980.093 

980.089 

- .004 

137. Indianapolis, Ind. 

39 

45.9 

86 

08.8 

217 

980.145 

- .067 

+ .003 

980.081 

980.090 

+ .009 

138. Springfield, Ill. 

39 

47.7 

89 

39.5 

183 

980.148 

- .056 

+ .005 

980.097 

980.089 

- .008 

139. Lebanon, Mo. 

37 

41.1 

92 

39.1 

385 

979.962 

- .119 

4- .012 

979.855 

979.874 

4- .019 

140. Joplin, Mo. 

37 

05.4 

94 

30.8 

303 

979.910 

- .094 

4- .001 

979.817 

979.841 

+ .024 

141. Fort Smith, Ark. 

35 

23.3 

94 

25.5 

135 

979.763 

- .042 

- .007 

979.714 

979.706 

- .008 

142. Texarkana, Ark. 

33 

25.5 

94 

02.5 

99 

979.598 

- .031 

4- .001 

979.568 

979.587 

+ .019 

143. Hot Springs, Ark. 

34 

30.1 

93 

03.6 

190 

979 .688 

- .059 

4- .004 

979.633 

979.659 

+ .026 

144. Alexandria, La. 

31 

18.6 

92 

26.0 

24 

979.425 

- .007 

4- .009 

979.427 

979.429 

4 - .002 

145. Laurel, Miss. 

31 

41.5 

89 

02.3 

77 

979.456 

- .024 

+ .011 

979.443 

979.465 

4- .022 

146. Richmond, Va. 

37 

32.2 

77 

26.1 

30 

979.948 

- .009 

4- .010 

979.949 

979.960 

4- .011 

147. Emporia, Va. 

36 

40.2 

77 

31 

37 

979.873 

- .011 

H- .015 

979.877 

979.898 

4- .021 

148. Greenville, N. C. 

35 

36.8 

77 

22.3 

17 

979.783 

- .005 

4- .019 

979.797 

979.787 

- .010 

149. Wilmington, N. C. 

34 

14.2 

77 

56.6 

9 

979 .666 

- .003 

4- .023 

979 .686 

979.663 

- .023 

150. Cheraw,“S.C. 

34 

42.0 

79 

54 

55 

979.705 

- .017 

+ .013 

979.701 

979.711 

4- .010 

































































































52 


TJ. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


Principal facts for 219 gravity stations in the United States —Continued. 


Number and name of station 

Latitude 

Longitude 

X 

Eleva¬ 

tion 

H 

Theo¬ 

retical 

gravity 

To 

Correc¬ 
tion for 
eleva¬ 
tion 

Correc¬ 
tion for 
topogra¬ 
phy and 
compen¬ 
sation 

Com¬ 
puted 
gravity 
at sta¬ 
tion 

9° 

Observed 
gravity 
at sta¬ 
tion 

9 

9~9c 


O 

/ 

o 

/ 

Meters 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

151. Charlotte, N. C. 

35 

13.8 

80 

50.8 

228 

979. 749 

-0.070 

+0.015 

979.694 

979.727 

+ 0.033 

15'2. Asheville, N. C. 

35 

35.9 

82 

33.3 

670 

979.781 

- .207 

+ .026 

979. 600 

979. 603 

+ .003 

153. Cleveland, Tenn. 

35 

09.4 

84 

52.9 

263 

979. 743 

- .081 

+ .002 

979. 664 

979. 049 

- .015 

154. Winston-Salem, N. C. 

36 

06.1 

80 

17 

284 

979.824 

- .088 

+ .012 

979. 748 

979. 718 

- .030 

155. Knoxville, Tenn. 

35 

57.7 

83 

55 

280 

979.812 

- .086 

- .001 

979.725 

979.712 

- .013 

156. Bristol, Va. 

36 

35.4 

82 

12 

514 

979. 866 

- .159 

+ .012 

979. 719 

979. 712 

- .007 

157. Homestead, Fla. 

25 

28.4 

80 

28.9 

4 

978.985 

- .001 

+ .029 

979.013 

978.985 

- .028 

158. Sebring, Fla. 

27 

30.2 

81 

27 

34 

979.131 

- .010 

+ .023 

979.144 

979.135 

- .009 

159. Titusville, Fla. 

28 

36.7 

80 

48.4 

3 

979.214 

- .001 

+ .023 

979.236 

979.243 

+ .007 

160. Leesburg, - Fla. 

28 

48.6 

81 

53 

30 

979.229 

- .009 

+ .021 

979.241 

979.235 

- .006 

161. Cedar Keys, Fla. 

29 

08.3 

83 

02.1 

2 

979.255 

- .001 

+ .016 

979.270 

979.257 

- .013 

162. Macon, Ga. 

32 

49.8 

83 

38 

99 

979.549 

- .031 

+ .007 

979.525 

979.552 

+ .027 

163. Albany, Ga. 

31 

34.3 

84 

09 

58 

979.446 

- .018 

+ .011 

979.439 

979.449 

+ .010 

164. Pensacola, Fla. 

30 

24.5 

87 

12.9 

2 

979.353 

- .001 

+ .014 

979.366 

979.300 

- .006 

165. Opelika, Ala. 

32 

38.5 

85 

22.8 

245 

979.533 

- .076 

+ .017 

979.474 

979.456 

- .018 

166. Huntsville, Ala. 

34 

43.8 

86 

35.2 

200 

979.707 

- .062 

+ .003 

979. 648 

979.633 

- .015 

167. Arkansas City, Ark. 

33 

36.5 

91 

12.2 

44 

979. 613 

- .014 

+ .005 

979. 604 

979. 600 

- .004 

168. Memphis, Term. 

35 

08.8 

90 

03.3 

80 

979. 742 

- .025 

+ .002 

979. 719 

979.740 

+ .021 

169. Mammoth Spring, Ark. 

36 

29.3 

91 

27 

156 

979. 857 

- .048 

- .002 

979. 807 

979.828 

+ .021 

170. Hopkinsville, Ky. 

36 

51.6 

87 

28 

176 

979.889 

- .054 

+ .006 

979.841 

979.855 

4- .014 

171. Danville, Ky. 

37 

38.9 

84 

46.4 

300 

979.958 

- .093 

+ .011 

979. 876 

979.855 

- .021 

172. Clifton Forge, Va. 

37 

49.1 

79 

49.0 

325 

979.973 

- .100 

- .003 

979. 870 

979.844 

- .026 

173. Greenville, Ala. 

31 

49.4 

86 

38 

130 

979.466 

- .040 

+ .016 

979.442 

979.439 

- .003 

174. Birmingham, Ala. 

33 

30.8 

86 

48.8 

179 

979.605 

- .055 

+ .011 

979.561 

979.536 

- .025 

175. Lexington, Va. 

37 

47.2 

79 

26.6 

324 

979.970 

- .100 

+ .005 

979.875 

979.859 

- .016 

176. Prestonsburg, Ky. 

37 

40.6 

82 

45.6 

193 

979.961 

- .060 

- .004 

979.897 

979.881 

- .016 

177. Traverse Citv, Mich. 

44 

45.8 

85 

37.2 

180 

980.595 

- .056 

+ .002 

980. 541 

980.550 

+ .009 

178. Seney, Mich. 

46 

20.8 

85 

57.6 

223 

980.738 

- .009 

+ .007 

980. 676 

980.685 

+ .009 

179. Oconto, Wis. 

44 

53.2 

87 

52.0 

181 

980.600 

- .050 

- .001 

980.549 

980. 532 

- .017 

180. Grand Rapids, Wis. 

44 

23.6 

89 

46 

300 

980.561 

- .094 

+ .005 

980.472 

980.438 

- .034 

181. Winona, Minn. 

44 

03.2 

91 

38.4 

201 

980.530 

- .062 

- .006 

980.4f>2 

980.485 

+ .023 

182. Baldwin, Wis. 

44 

57.8 

92 

23 

342 

980.613 

- .106 

+ .006 

980.513 

980.471 

- .042 

183. Cumberland, Wis. 

45 

32.4 

92 

00 

380 

980.665 

- .117 

+ .008 

980.556 

980.515 

- .041 

184. Cambridge, Minn. 

45 

34.0 

93 

11 

303 

980.067 

- .094 

+ .002 

980. 575 

980.556 

- .019 

185. Brainerd, Minn. 

46 

21.3 

94 

12.1 

367 

980. 739 

- .113 

+ .003 

980.629 

980.049 

+ .020 

186. Aberdeen, S. Dak. 

45 

27.5 

98 

29.0 

396 

980. 657 

- .122 

- .005 

980.530 

980.550 

+ .020 

187. Faith, S. Dak. 

45 

01.3 

102 

04 

786 

980. 018 

- .243 

+ .006 

980.381 

980.404 

+ .023 

188. Marmarth, N. Dak. 

46 

18.4 

103 

53 

822 

980.734 

- .254 

- .002 

980.478 

980.521 

+ .043 

189. Towner, N. Dak. 

48 

20.3 

100 

26 

451 

980.917 

- .139 

- .004 

980.774 

980.814 

+ .040 

190. Crosby, N. Dak. 

48 

54.7 

103 

19 

598 

980.969 

- .185 

+ .001 

980.785 

980.810 

+ .025 

191. Crookston, Minn. 

47 

46.2 

96 

36 

260 

980. 866 

- .080 

- .006 

980.780 

980.799 

+ .019 

192. Poplar, Mont. 

48 

06.8 

105 

12 

608 

980. 897 

- .188 

- .009 

980.700 

980.727 

+ .027 

193. Miles City, Mont. 

46 

24.2 

105 

50 

718 

980.743 

- .222 

- .020 

980. 501 

980. 539 

+ .038 

194. Huntley, Mont. 

45 

54.0 

108 

19.6 

919 

980.697 

- .284 

- .022 

980.391 

980.410 

+ .019 

195. Lander, Wyo. 

42 

50.0 

108 

43 

1635 

980.420 

- .505 

- .028 

979.887 

979.914 

+ .027 

196. Fairbault, Minn. 

44 

17.8 

93 

15 

301 

980.553 

- .093 

.000 

980.460 

980.504 

+ .044 

197. St. James, Minn. 

43 

58.6 

94 

30 

330 

980. 523 

- .102 

+ .002 

980.423 

980.437 

+ .014 

198. Edgemont, S. Dak. 

43 

17.7 

103 

49.2 

1066 

980.462 

- .329 

- .012 

980.121 

980.183 

+ .062 

199. Dawson, Minn. 

44 

55.8 

96 

01 

323 

980. 610 

- .100 

- .003 

980.507 

980.532 

+ .025 

200. Cokato, Minn. 

45 

04.5 

94 

12 

319 

980.623 

- .098 

+ .003 

980.528 

980.542 

+ .014 

201. Wasta, S. Dak. 

44 

04.2 

102 

25 

706 

980.532 

- .218 

- .013 

980.301 

980.339 

+ .038 

202 . Moorcroft, Wyo. 

44 

15.5 

104 

58 

1295 

980.549 

- .400 

+ .005 

980.154 

980.183 

+ .029 

203. Duluth, Mum. 

40 

47.0 

92 

06.4 

216 

980.777 

- .007 

- .010 

980. 700 

980.758 

+ .058 

204. Osage, Iowa. 

43 

16.8 

92 

47 

356 

980.460 

- .110 

+ .007 

980.357 

980.339 

- .018 

205. Randolph, Nebr. 

42 

23.0 

97 

19 

515 

980.380 

- .159 

+ .005 

980.226 

980.236 

+ .010 

206. Valentine, Nebr. 

42 

52.3 

100 

31 

785 

980.423 

- .242 

+ .004 

980.185 

980.211 

+ .026 

207. Wheeling, W. Va. 

40 

04.0 

80 

43.4 

205 

980.172 

- .063 

- .003 

980.106 

980.085 

- .021 

208. Leon, Iowa. 

40 

44.6 

93 

43 

344 

980.232 

- .106 

+ .007 

980.133 

980.133 

.000 

209. Laurel, Md. 

39 

06.3 

76 

51.0 

54 

980.086 

- .017 

+ .007 

980.076 

980.118 

+ .042 

210. Harrisburg, Pa. 

40 

16.0 

76 

53.1 

104 

980.190 

- .032 

+ .002 

980.160 

980.139 

- .021 

211. Pittsburg, Pa. 

40 

27.4 

80 

00.6 

235 

980.206 

- .073 

.000 

980.133 

980.118 

- .015 

212. Rockville, Md. 

39 

04.9 

77 

08.8 

129 

980.084 

- .040 

+ .013 

980.057 

980. Ill 

+ .054 

213. Upper Marlboro, Md. 

38 

49.0 

76 

45.2 

12 

980.061 

- .004 

+ .007 

980.004 

980.085 

+ .021 

214. Fairfax, Va. 

38 

47.7 

77 

19.6 

115 

980.059 

- .035 

+ .011 

980.035 

980.079 

+ .044 

215. Crisfield, Md. 

37 

58.8 

75 

50.7 

1 

979.987 

.000 

+ .019 

980.006 

979.985 

- .021 

216. Fredericksburg, Va. 

38 

18.1 

77 

27.5 

16 

980.015 

- .005 

+ .004 

980.014 

980.027 

+ .013 

217. Dover, Del. 

39 

09.7 

75 

32.0 

12 

980.092 

- .004 

+ .013 

980.101 

980.099 

- .002 

218. North Tamarack, Mich. 

47 

15.8 

88 

27.0 

370 

980.821 

- .114 

+ .020 

980.727 

980. 706 

+ .039 

219. Hagerstown, Md. 

39 

38.5 

77 

43.5 

166 

980.134 

- .051 

+ .006 

980.089 

980.048 

- .041 



























































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


53 


GRAVITY FORMULA OF 1912. 

Iii Special Publication No. 12 a new formula was derived which it was believed more nearly 
represented the conditions in the United States than did the Helmert formula of 1901. The 
new formula was found to be 

To = 978.038 (1 +0.005304 sin 2 0- 0.000007 sin 2 2 0) 

(See p. 25, Special Publication No. 12.) 

The formula advocated by the writer in that publication was the above formula modified 
by making the second term 0.005302, the same value as in Helmert’s formula. The adopted 
1912 formula is then 

To — 978.038 (1 + 0.005302 sin 2 0-0.000007 sin 2 2 0) 

The investigations made in 1912 were based upon the values of gravity in the United States 
computed by this formula. 

In the preceding table the mean value of g-g c is + 0.005 dyne and the probable error of asingle 
value is ±0.016 dyne. The residuals for the two Seattle stations (Nos. 53 and 56) are each 
— 0.085 dyne, which is more than five times the probable error of a single value. This evi¬ 
dently indicates a very abnormal condition in the earth’s crust near Seattle, and, it is believed, 
these two values should not be considered in taking means for the purpose of correcting the 
Helmert formula. 

After rejecting the Seattle stations, the mean with regard to sign of g-g c is +0.006 + 0.0011 
dyne. As this is more than five times its own probable error, it is believed it represents a 
real error in the first term of the Helmert formula. In 1912 the mean value of g-g 0 , after 
rejecting Seattle, was + 0.008 dyne. This was the value also found by a least square solution. 
As the 1912 formula would be modified by only 0.002 dyne if the mean from the above table 
were applied as a correction to the Helmert formula, it was thought better not to change from 
the 1912 value. 

Later on in this volume (pp. 122 to 129) there are given various gravity formulas derived 
from stations in the United States and other countries from several groupings and upon 
different assumptions. 

The 1912 anomalies used frequently in this volume were computed by the 1912 formula 
which is given above, the depth of compensation being 113.7 km. 

The 1916 anomalies were computed by the 1916 formula for the United States and with 
a depth of 60 km. This formula is shown on page 123. For convenience it is inserted below. 

Formula of 1916: 

To = 978.040 (1 + 0.005302 sin 2 0-0.000007 sin 2 2 0) 

A plus sign of an anomaly means that at the station in question the observed intensity of 
gravity is in excess of that which would occur if the assumed conditions were true as to densi¬ 
ties of the topography, and if the compensation were complete, uniformly distributed to the 
depth of compensation, and directly under the topographic features. If the anomaly is 
negative, the observed gravity is less than it would be if the ideal conditions obtained. A 
part of the anomaly is due to errors in the assumed densities, to departures from the depth of 
compensation with which the effect of the compensation is computed, and to erroneous values 
for the terms in the gravity formula. Errors in the assumed elevation of the station and in 
the contour maps used to compute the corrections for topography and isostatic compensation 
also cause a small part of the anomaly, as do also errors in the observations to determine the 
periods of the pendulums, and slight changes in the pendulums between standardizations. 

An elaborate discussion of the various sources of error is given on pages 86 to 96 of Special 
Publication No. 10. It is shown that the average probable error of a computed value of 
gravity is ±0.003 dyne. It is not believed to be necessary to repeat that discussion of errors 
in this volume. The only modification of the statements made in Special Publication No. 10 that 
seems to be needed is discussed in connection with the correction for elevation, pages 93-96. 


54 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


PRINCIPAL FACTS FOR 42 STATIONS IN CANADA. 

Tho Geodetic Survey of Canada has recently been actively engaged in establishing gravity 
stations within its area, and in response to a request from the Superintendent of the United 
States Coast and Geodetic Survey the Director of the Canadian Survey generously placed at 
the author’s disposal the unpublished data regarding the 42 Canadian stations. These data 
arc given in the following table. They are used in computing gravity formulas (see pp. 113 to 
131) and in the gravity anomaly maps (fig. 11, in the pocket at the end of the volume) and in 
a study of the relations between the anomalies and the geologic formation. 

The observations and the reduction for topography and isostatic compensation were made 
by F. A. McDiarmid, of the Geodetic Survey of Canada. 

The observed values are on the Potsdam system, and the computed values are based 
upon Helmert’s formula of 1901 and the gravity reduction tables given on pages 30 to 47 of 
Special Publication No. 10. The data are therefore similar to those for the United States 
stations given on pages 50-52 of this volume. 


Principal facts for 42 stations in Canada. 


Number and name of station 

Latitude 

0 

Longitude 

X 

Elevation 

H 

Theoreti¬ 

cal 

gravity 

To 

Correc¬ 
tion for 
eleva¬ 
tion 

Correc¬ 
tion for 
topogra¬ 
phy and 
compen- 
station 

Com¬ 
puted 
gravity 
at sta¬ 
tion 

9 o 

Observed 
gravity 
at sta¬ 
tion 

9 

9~9c 

Hayford 

anomaly, 

1912 


o t n 

ft m s 

Meters 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

1. Ottawa. 

45 23 39 

5 02 52 

83 

980. 651 

-0.026 

0.000 

980. 625 

980. 615 

-0.010 

-0.018 

2. Maniwaki. 

46 22 28 

5 03 55 

169 

980. 740 

- .052 

- .001 

980.687 

980. 685 

- .002 

- .010 

3. Kingston. 

44 14 37 

5 05 55 

79 

980. 547 

- .024 

+ .008 

980.531 

980. 527 

— .004 

- .012 

4. Roberval. 

48 30 54 

4 48 54 

107 

980. 933 

- .03.3 

- .015 

980.885 

980. 865 

- .020 

- .028 

5. Tadoussac. 

48 08 25 

4 38 52 

12 

9S0.900 

- .004 

- .004 

980. 892 

980. 901 

+ .009 

4- .001 

6. Portneuf. 

46 42 32 

4 47 35 

59 

980. 770 

- .018 

+ .005 

980. 757 

980. 760 

+ .003 

- .005 

7. St. Jerome. 

45 46 34 

4 56 00 

107 

980.686 

- .033 

+ .006 

980.659 

980.678 

+ .019 

+ .011 

8. Ste. Anne de Bellevue. 

45 24 27 

4 55 46 

34 

980.653 

- .010 

+ .003 

980. 646 

980.660 

4- .014 

+ .006 

9. Mattawa. 

46 18 43 

5 14 49 

170 

980. 734 

- .052 

- .013 

980.669 

9,80. 647 

- .022 

— .030 

10. Liskeard. 

47 30 34 

5 18 41 

194 

980.843 

- .060 

- .004 

980. 779 

980.785 

+ .006 

- .002 

11. Cochrane. 

49 03 44 

5 24 05 

277 

980. 983 

- .085 

- .004 

980. 894 

980. 880 

- .014 

- .022 

12. Sault Ste. Marie. 

46 30 26 

5 37 18 

186 

980. 752 

- .057 

- .005 

980.690 

980. 677 

- .013 

- .021 

13. Chapleau. 

47 50 27 

5 33 37 

4.30 

980. 872 

- . 133 

+ .012 

980. 751 

980.763 

4- .012 

+ .004 

14. Port Arthur. 

48 26 00 

5 56 52 

189 

980. 926 

- .058 

- .014 

980. 854 

980. 817 

- .037 

— .045 

15. Rose Point. 

45 19 02 

5 20 10 

183 

980.644 

- .056 

+ .001 

980. 589 

980. 603 

4- .014 

+ .006 

16. Whitby. 

43 52 43 

5 15 46 

84 

980. 514 

- .026 

- .004 

980. 484 

9S0. 458 

- .026 

- .034 

17. Woodstock, Ontario. 

43 08 3.3 

5 23 08 

299 

980. 448 

- .093 

- .002 

980.353 

980.349 

- .004 

— .012 

18. Windsor. 

42 19 16 

5 32 10 

178 

980.373 

- .055 

.000 

980.318 

980.338 

+ .020 

4- .012 

19. St. John. 

45 16 03 

4 24 20 

33 

980. 640 

- .010 

+ .016 

980.646 

980.660 

+ .014 

+ .006 

20. Moncton. 

46 05 04 

4 19 09 

14 

980. 713 

- .004 

+ .014 

9S0. 723 

980.725 

+ .002 

- .006 

21. Charlottetown. 

46 13 55 

4 12 30 

8 

980. 727 

- .002 

-f .013 

980. 738 

980. 7.30 

- .008 

- .016 

22. Sydney. 

46 08 21 

4 00 47 

12 

980. 719 

- .004 

+ .014 

980. 729 

980. 728 

- .001 

— .009 

23. Truro. 

45 21 40 

4 13 06 

IS 

980. 649 

- .006 

+ .014 

980. 657 

980.659 

+ .002 

- .006 

24. Halifax. 

44 40 47 

4 14 15 

9 

980. 587 

- .003 

+ .008 

980. 592 

980. 571 

- .021 

— .029 

25. Yarmouth. 

43 50 07 

4 24 29 

9 

980. 510 

- .003 

+ .014 

980.521 

980.540 

+ .019 

+ .011 

26. Woodstock, New Brunswick. 

46 09 02 

4 30 18 

56 

9,SO 720 

— 017 

-f (W 

Q^O 711 

qso 

015 


27. Edmundston. 

47 22 11 

4 33 18 

148 

980. 830 

- .046 

- .010 

98a 774 

980. 771 

— ! 003 

— .011 

28. Bathurst. 

47 37 10 

4 22 36 

5 

980. 853 

- .002 

.000 

9,80. 851 

980.833 

- .018 

- .026 

29. Perce. 

48 31 33 

4 16 51 

6 

980.935 

- .002 

- .002 

980. 931 

980. 947 

+ .016 

4 .008 

30. Kenora. 

49 46 00 

6 18 00 

330 

981.046 

- . 102 

+ .018 

980.962 

980.971 

4- .009 

+ .001 

31. Winnipeg. 

49 54 23 

6 28 32 

231 

981. 057 

- .071 

+ .002 

980. 988 

9,80. 987 

- .001 

- .009 

32. Brandon. 

49 50 54 

6 39 47 

366 

981.053 

- .113 

- .002 

980. 938 

980. 953 

+ .015 

4- .007 

33. Moose Jaw. 

50 23 26 

7 02 07 

541 

981.101 

- . 167 

+ .003 

980.937 

980. 940 

+ .003 

— .005 

34. Medicine Hat. 

50 02 25 

7 22 40 

664 

981.070 

- .205 

- .002 

980. 863 

980. 865 

4- .002 

— .006 

35. Calgary. 

51 02 43 

7 36 15 

1044 

981.160 

- .322 

- .022 

980.816 

980.820 

+ .004 

— .004 

36. Banff. 

51 10 53 

7 42 18 

1376 

981.172 

- .425 

- .012 

980. 735 

980. 750 

4- .015 

4- .007 

37. Field. 

51 23 42 

7 45 59 

1239 

981. 190 

- .382 

- .060 

980. 748 

980. 745 

- .003 

— .011 

38. Revelstoke. 

50 59 48 

7 52 47 

453 

981.155 

— .140 

- .080 

980. 935 

980. 900 

- .035 

— .043 

39. Kamloops. 

50 40 42 

8 01 18 

352 

981.127 

- .109 

- .073 

980. 945 

980. 944 

- .001 

— .009 

40. North Bend. 

49 52 17 

8 05 48 

152 

981. 055 

- .047 

- .122 

980.886 

980. 886 

.000 

- .008 

41. Glacier. 

51 15 44 

7 49 58 

1248 

981. 179 

- .385 

- .066 

980. 728 

980. 738 

+ .010 

4- .002 

42. Vancouver. 

49 16 49 

8 12 27 

6 

981.002 

- .002 

- .046 

980. 954 

980. 946 

- .008 

- .016 













































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


55 


PRINCIPAL FACTS FOR 73 STATIONS IN INDIA. 

In the office of the Survey of India the Hayford reductions have been made for 73 stations 
in that country. The data regarding them are published in a report of the Survey of India, title 
of which is given in a footnote on page 45. 

The corrections for elevations as given in the Indian report wore computed by the formula: 

Correction for elevation = — 

in which a mean value of the radius of the earth, R, is taken as 20,900,000 feet. H is the eleva¬ 
tion of the station in feet. These corrections are given in the column headed “ Correction for 
elevation, Indian,” in the table following. In the column headed “Correction for elevation, 
U. S. C. & G. S.” are given the corrections computed by the formula: 

Correction for elevation = —0.0003086 H 

in which II is the elevation of the station in meters. The maximum difference is 0.006 dyne at 
station No. 95, Sandakphu. The results by the second formula have been used in the discus¬ 
sions in this volume, as this formula is somewhat more accurate in theory.® 

The reductions for topography and compensation were computed in much the same way 
as is done by the United States Coast and Geodetic Survey. For zones 18 to 1 the methods and 
constants are identical. For the inner zones which are lettered from A to O a slightly different 
gravitation constant was used. It is 657 X 10~ 10 for C. G. S. units, while the one used by the 
United States Coast and Geodetic Survey is 667.3 X 10~ 10 . The depth of compensation used is 
70 miles, 112.65 km., instead of 113.7 km. The compensation was distributed from sea level 
instead of from the surface of the earth. For ocean areas the Indian Survey distributed the 
compensation from the bottom to a depth of 70 miles (112.65 km.) below the surface of the 
water, while the United States Coast and Geodetic Survey distributes the compensation from 
the ocean bottom to a depth of 113.7 km. below the ocean bottom. 

These changes in the method of computing the topography and the compensation do not 
make any differences which need be considered in our discussions. We may consider the India 
data similar to those which we have for the United States, Canada, and Europe, all of which 
are based upon identical methods and constants. 

In the fourth column from the last in the following table are given the gravity anomalies 
based upon the Hayford reduction and the Helmert formula of 1901 with 978.030 as the first 
term and with the Indian corrections for elevation of station. In next to the last column are 
given the anomalies which are similar in every way to those just mentioned except that the 
United States correction for elevation is applied instead of the Indian correction. The theoretical 
values of gravity at sea level as computed with the Helmert formula are given in the fifth column. 

The observed values given in the following table are based upon the value of 979.063 dynes 
for Dehra Dim. The value of gravity at that station as given in the latest report ol the Inter¬ 
national Geodetic Association is 979.065 dynes. 

«“Ueber die Reduction der auf der physischen Erdoberflaehe beobachteten Schweresbeschleunigungen auf ein gemeinsames Niveau” by 
Helmert, Sitzungsberichte der Koniglich Preussischen Akademie der Wissenschaften, volumes for 1902, p. 843, and 1903, p. 650. 





56 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40 


Principal facts for 73 stations in India. 


Number and name of 
station 

Latitude 

0 

Longitude 

X 

Eleva¬ 

tion 

H 

Theoret¬ 

ical 

gravity 

To 

Correc¬ 

tion 

eleva¬ 

tion 

(Indi¬ 

an) 

Correc¬ 
tion for 
topogra¬ 
phy and 
compen¬ 
sation 

Com¬ 
puted 
gravity at 
station 

9e 

Observed 
gravity ai 
station 

g 

Q~Qo 

(Indian) 

Correc¬ 
tion for 
eleva¬ 
tion 

(U. S. C. 
& G. S.) 

9-9 o 

(U.S.C 

&G.S.) 

Hay- 

ford 

anom¬ 

aly, 

1912 

1. Agra. 

Off/ 

Of ft 

Meters 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

27 10 20 

78 01 07 

163 

979.107 

-0.050 

-0.018 

979.039 

979.056 

+0.017 

-0.050 

+0.017 

+0.009 

2. Aligarh. 

27 53 32 

78 00 31 

187 

979.160 

- .057 

- .021 

979.082 

979.075 

- .007 

- .058 

- .006 

- .014 

3. Allahabad. 

25 25 55 

81 55 

88 

978.982 

- .027 

- .021 

978.934 

978.943 

-f .009 

- .027 

+ .009 

+ .001 

4. Amgaon. 

21 21 31 

80 28 

315 

978.715 

- .097 

- .001 

978.617 

978. 614 

- .003 

- .097 

- .003 

- .011 

5. Amraoti. 

20 55 50 

77 45 40 

342 

978.689 

— .105 

- .001 

978.583 

978.609 

+ .026 

- .106 

+ .027 

+ .019 

6. Arrah. 

25 34 10 

84 39 

57 

978.992 

- .018 

- .028 

978.946 

978.918 

- .028 

- .018 

- .028 

- .036 

8. Asigarh. 

21 28 10 

76 17 50 

633 

978.721 

- .194 

+ .027 

978.554 

978.584 

+ .030 

- .195 

+ .031 

+ .023 

9. Badnur. 

21 54 10 

77 54 10 

641 

978. 748 

- .197 

+ .018 

978. 569 

978.607 

+ .038 

- .198 

+ .039 

+ .031 

12. Bhopal. 

23 15 58 

77 25 

497 

978.S35 

- .153 

+ .007 

978.689 

978.711 

+ .022 

- .153 

+ .022 

+ .014 

13. Bilaspur. 

22 03 53 

82 12 

268 

978.758 

- .082 

- .008 

978.668 

978.681 

+ .013 

- .0S3 

+ .014 

+ .006 

14. Bina. 

24 10 41 

78 11 46 

413 

978.896 

- .127 

.000 

978. 769 

978.795 

+ .026 

- .127 

+ .026 

+ .018 

15. Buxar. 

25 34 42 

83 59 

63 

978.992 

- .019 

- .026 

978.947 

978.933 

— .014 

- .019 

- .014 

- .022 

16. Chatra. 

24 12 40 

88 23 27 

20 

978.898 

- .006 

— .019 

978.873 

978.878 

+ .005 

- .006 

+ .005 

- .003 

17. Colaba. 

18 53 45 

72 48 47 

10 

978.571 

- .003 

.000 

978.568 

978.631 

+ .063 

- .003 

+ .063 

+ .055 

18. Cuttack. 

20 29 05 

85 52 01 

28 

978.662 

- .009 

.000 

978.653 

978.659 

+ .006 

- .009 

+ .006 

- .002 

19. Daltonganj. 

24 02 05 

84 04 

215 

978.886 

- .066 

- .018 

978.802 

978.827 

+ .025 

- .066 

+ .025 

+ .017 

20. Damoh. 

23 49 54 

79 26 

370 

978.873 

- .114 

- .005 

978. 754 

978. 758 

+ .004 

- .114 

+ .004 

- .004 

22. Dehra Dun. 

30 19 29 

78 03 15 

682 

979.347 

- .210 

- .080 

979.057 

979.063 

+ .006 

- .210 

+ .006 

- .002 

24. Dholpur. 

26 42 01 

77 54 47 

176 

979.072 

- .054 

- .015 

979.003 

978.999 

a - .005 

- .054 

- .005 

- .013 

26. Ellichpur. 

21 18 20 

77 30 40 

401 

978.711 

- .123 

- .001 

978.587 

978.618 

+ .031 

- .124 

+ .032 

+ .024 

29. Gaya. 

24 47 42 

85 00 

110 

978.938 

- .034 

- .023 

978.881 

978.884 

+ .003 

- .034 

+ .003 

- .005 

30. Gesupur. 

28 33 02 

77 42 03 

211 

979.210 

- .065 

- .025 

979.120 

979.125 

+ .005 

- .065 

+ .005 

- .003 

31. Goona. 

24 38 48 

77 19 13 

478 

978.928 

- .147 

+ .007 

978. 788 

978.807 

+ .019 

- .148 

+ .020 

+ .012 

32. Gorakhpur. 

26 44 58 

83 23 

78 

979.076 

- .024 

- .046 

979.006 

978.936 

- .070 

- .024 

- .070 

- .078 

33. Gwalior. 

26 13 57 

78 12 49 

201 

979.039 

- .062 

- .012 

978.965 

978.95S 

- .007 

- .062 

- .007 

- .015 

35. Hathras. 

27 36 52 

78 03 22 

179 

979.139 

— . 055 

- .020 

979.064 

979.075 

+ .011 

- .055 

+ .011 

+ .003 

37. Hoshangabad. 

22 45 00 

77 43 50 

305 

978.802 

- .094 

- .010 

978.698 

978.719 

+ .021 

- .094 

+ .021 

+ .013 

38. Jacobabad. 

28 16 34 

68 27 05 

56 

979.189 

- .017 

- .024 

979.148 

979.186 

+ .038 

- .017 

+ .038 

+ .030 

39. Jalgaon. 

21 00 00 

75 33 50 

232 

978.693 

- .071 

- .009 

978.613 

978.633 

+ .020 

- .071 

+ .020 

+ .012 

40. Jalpaiguri. 

26 31 16 

88 44 13 

82 

979.060 

- .025 

- .093 

978.942 

978.922 

- .020 

- .025 

- .020 

- .028 

41. Japla. 

24 31 58 

84 00 

144 

978.920 

- .044 

- .022 

978.854 

978.856 

+ .002 

- .044 

+ .002 

- .006 

42. Jhansi. 

25 27 02 

78 33 43 

262 

978.983 

- .080 

- .007 

978.896 

978. 910 

+ .014 

- .081 

+ .015 

+ .007 

43. Jubbulpore. 

23 08 54 

79 59 

447 

978.828 

- .137 

- .002 

978.689 

978. 719 

+ .030 

- .138 

+ .031 

+ .023 

44. Kaliana. 

29 30 55 

77 39 06 

247 

979.284 

- .076 

- .047 

979.161 

979.154 

- .007 

- .076 

- .007 

- .015 

45. Kalianpur. 

24 07 11 

77 39 17 

537 

978.892 

- .165 

+ .011 

978.738 

978. 777 

+ .039 

- .166 

+ .040 

+ .032 

48. Katni. 

23 50 25 

80 26 

382 

978.873 

- .117 

- .006 

978. 750 

978.757 

-t- .007 

- .118 

+ .008 

.000 

50. Khandwa. 

21 49 30 

76 21 30 

309 

978. 743 

- .095 

- .003 

978.645 

978.692 

4- .047 

- .095 

+ .047 

+ .039 

51. Khurja. 

28 14 19 

77 51 53 

198 

979.186 

- .061 

- .024 

979.101 

979.082 

- .019 

- .061 

- .019 

- .027 

52. Kisnapur. 

25 02 26 

88 28 29 

34 

978.955 

- .011 

- .027 

978.917 

978.956 

+ .039 

- .011 

+ .039 

+ .031 

55. Lalitpur. 

24 41 29 

78 24 26 

365 

978.931 

- .112 

- .003 

978.816 

978.814 

- .002 

- .113 

- .001 

- .009 

58. Madras. 

13 04 08 

80 14 54 

6 

978.294 

- .002 

+ .040 

978.332 

978.279 

- .053 

- .002 

- .053 

- .061 

59. Maihar. 

24 15 38 

SO 48 

354 

978.902 

- .109 

- .006 

978. 787 

978. 784 

- .003 

— .109 

— .003 

— .011 

60. Majhauli Raj. 

26 17 46 

83 58 

67 

979.043 

- .021 

- .037 

978.985 

978.928 

- .057 

- .021 

- .057 

— .065 

65. Mhow. 

22 33 10 

75 45 40 

580 

978. 789 

- .178 

+ .024 

978.635 

978.620 

- .015 

- .179 

- .014 

- .022 

66. Mian Mir. 

31 31 37 

74 22 32 

216 

979.442 

- .066 

- .033 

979.343 

979.383 

+ .040 

- .067 

+ .041 

+ .033 

67. Moghal Sarai. 

25 17 03 

83 06 

78 

978.972 

- .024 

- .024 

978.924 

978.919 

- .005 

- .024 

- .005 

- .013 

70. Monghyr. 

25 22 53 

86 28 

47 

978.979 

- .014 

- .031 

978.934 

978.909 

- .025 

— .014 

- .025 

- .033 

71. Montgomery. 

30 39 47 

73 06 18 

170 

979.373 

- .052 

- .019 

979.302 

979.321 

+ .019 

- .052 

+ .019 

+ .011 

72. Mortakka. 

22 13 20 

76 02 50 

176 

978. 768 

- .054 

- .016 

978.698 

978. 703 

+ .005 

- .054 

+ .005 

- .003 

73. Mukhtiara. 

22 23 40 

75 58 40 

282 

978. 779 

- .087 

- .009 

978.683 

978.664 

- .019 

- .087 

- .019 

- .027 

75. Mussoorie (Camel’s 













Back). 

30 27 35 

78 04 32 

2110 

979.357 

- .649 

+ .032 

978.740 

978.793 

+ .053 

- .651 

+ .055 

+ .047 

77. Muttra. 

27 28 25 

77 41 48 

171 

979.129 

- .053 

- .019 

979.057 

979.072 

-f .015 

— .053 

+ .015 

+ .007 

78. Muzaffarpur. 

26 07 05 

85 25 

55 

979.031 

- .017 

- .038 

978.976 

978.934 

- .042 

- .017 

- .042 

— .050 

82. Ootacamund. 

11 24 37 

76 42 03 

2254 

978.232 

- .692 

+ .183 

977. 723 

977.735 

+ .012 

- .696 

+ .016 

+ .008 

83. Pathankot. 

32 16 33 

75 39 03 

332 

979.503 

- .101 

- .088 

979.314 

979.237 

a— .076 

- .102 

- .075 

- .083 

84. Pendra. 

22 46 41 

82 00 

608 

978.804 

- .187 

+ .013 

978.630 

978.638 

+ .008 

- .188 

+ .009 

+ .001 

87. Quetta. 

30 12 15 

67 00 41 

1682 

979.337 

- .517 

+ .024 

978.844 

978.851 

+ .007 

— .519 

+ .009 

+ .001 

88. Raipur. 

21 13 56 

81 41 

304 

978. 707 

- .093 

+ .001 

978.615 

978.612 

- .003 

- .094 

- .002 

- .010 

89. Rajpur. 

30 24 12 

78 05 47 

1012 

979.353 

- .311 

- .066 

978.976 

979.002 

+ .026 

- .312 

+ .027 

+ .019 

91. Ranchi. 

23 23 05 

85 19 

661 

978.843 

- .203 

+ .021 

978.661 

978.691 

+ .030 

- .204 

+ .031 

+ .023 

93. Roorkee. 

29 52 20 

77 53 59 

264 

979.311 

- .081 

- .057 

979.173 

979.129 

- .044 

- .081 

- .044 

- .052 

94. Salem. 

11 40 05 

78 09 10 

289 

978.241 

- .089 

+ .012 

978.164 

978.116 

- .048 

— .089 

- .048 

— .056 

95. Sandakphu. 

27 06 06 

88 00 15 

3586 

979.102 

-1.101 

+ .141 

978.142 

978.190 

+ .048 

—1.107 

+ .054 

+ .046 

96. Sasaram. 

24 57 21 

83 59 

104 

978.949 

- .032 

- .023 

978.894 

978.903 

+ .009 

- .032 

+ .009 

+ .001 

97. Saugor. 

23 51 47 

78 48 

536 

978.875 

- .165 

+ .010 

978.720 

978.731 

+ .011 

- .165 

+ .011 

+ .003 

98. Seoni. 

22 05 29 

77 29 

619 

978. 760 

- .190 

+ .016 

978.586 

978.622 

+ .036 

- .191 

+ .037 

+ .029 

99. Shahpur. 

22 11 30 

77 54 10 

392 

978.766 

- .120 

- .006 

978.640 

978.663 

+ .023 

- .121 

+ .024 

+ .016 

.00. Sibi. 

29 32 46 

67 52 31 

132 

979. 286 

- .040 

- .067 

979.179 

979.119 

a — .059 

- .041 

- .058 

— .066 

101 . Siliguri. 

26 41 47 

88 24 50 

118 

979.072 

- .036 

- .110 

978.926 

978.887 

- .039 

- .036 

- .039 

— .047 

.03. Sipri. 

25 25 52 

77 39 25 

467 

978. 982 

- .144 

+ .009 

978.847 

978.876 

+ .029 

- .144 

+ .029 

+ .021 

106. Ujjain. 

23 11 00 

75 47 

491 

978.830 

- .151 

+ .009 

978.688 

978.677 

- .011 

- .152 

- .010 

— .018 

.07. Umaria. 

23 31 37 

80 54 

457 

978.853 

- .140 

- .002 

978. 711 

978.740 

+ .029 

- .141 

+ .030 

+ .022 

08. Yercaud. 

11 46 56 

78 12 29 

1369 

978.245 

- .420 

+ .116 

977.941 

977.908 

- .033 

- .422 

- .031 

- .039 


“ Theanomalies for stations 24,83, and 100 are reproduced as given in the original source, although the data as taken from there to three decimals 
°;i <ly I’ e ^ n( , e ? eale i h 5 re U ve an anomaly differing by 0.001 dyne. It is supposed that the discepancy is due to additional decimals used in the 
computation but omitted in the published statement. The anomalies in other columns correspond to the values given in this column. 











































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


57 


PRINCIPAL FACTS FOR 40 STATIONS NOT IN THE UNITED STATES PROPER, CANADA, OR INDIA. 

The following table contains the principal facts for 40 stations outside of Canada, India, 
and the United States proper. The data for stations Nos. 1 to 36, inclusive, except the cor¬ 
rection for topography and compensation and the resulting g c , were obtained from the reports 
of the International Geodetic Association. The correction for topography and compensation 
of Nos. 1 to 27 was computed by the United States Coast and Geodetic Survey for depth of 
compensation of 113.7 km. in the usual way, and for Nos. 28 to 36 it was computed by Mr. Niet- 
hammcr from Hayford’s tables, and is taken from the “Proces Verbal de la 56me stance de la 
commission geodesique Suisse,” Neuchatel, 1910. Stations 37 to 40 are from a publication of 
the Royal Italian Geodetic Commission, “ Determinazioni di Gravita relativa compiute nel 
1912,” byReina and Cassinis, Rome, 1913. The correction for topography and isostatic com¬ 
pensation is there computed for a depth of 120 km. and contains the error noted in the foot¬ 
note on page 98 of this publication. Tho error has been corrected and an approximate allowance 
made to change the depth to 113.7 km. The combined effect of these two changes was to 
reduce the anomaly in each case by 0.001 dyne. 

The theoretical gravity throughout the table is based on Helmert’s formula of 1901, 
Potsdam system. 

It is intended that the several tables of principal facts (pp. 50 to 57) shall contain data 
for all well-observed gravity stations on land known to this Survey for which corrections, 
by Hayford’s method, for topography and isostatic compensation have been computed for the 
depth 113.7 km. In the Comptes Rendus de la 17me Conference geodesique de 1’Association 
Geodesique Internationale, lime Volume (Rapports Speciaux) pages 41 and 404, are given lists 
of corrections for topography and compensation for stations chiefly in Africa that are not 
included in this publication owing to lack of information as to the assumptions and methods 
underlying the computation. 

Principal facts for 40 stations not in the United States proper, Canada, or India. 


Number and name of station 

Latitude 

<t> 

Longi¬ 

tude 

X 

Elevation 

H 

Theoret¬ 

ical 

gravity 

To 

Correc¬ 
tion for 
eleva¬ 
tion 

Correc¬ 
tion for 
topogra¬ 
phy and 
compen¬ 
sation 

Com¬ 
puted 
gravity at 
station 

9° 

Observed 
gravity at 
station 

9 

9~9c 

Hayford 

anomaly, 

1912 


o / 

O t 

Meiers 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

Dynes 

1. Stilfserjoch (Stelvio Pass), Austria... 

46 31.8 

10 27.4 

2760 

980.755 

—0.852 

+0.152 

980.055 

9S0.045 

—0.010 

—0.018 

2. Frunze nhohe, Austria. 

46 32.0 

10 29.0 

2188 

980.755 

— .675 

H- . 0S7 

980.167 

980.153 

— .014 

— .022 

3. Schneekoppe, Germany. 

50 44.2 

15 44.6 

1605 

981.132 

— .495 

+ .110 

980.747 

980.776 

4- .029 

+ .021 

4. Alte Bruch, Germany....... 

50 45. 7 

15 44.6 

917 

981.134 

— .283 

+ .060 

980.911 

980.930 

+ .019 

+ .011 

5. Brocken, Germany.^. 

51 48.0 

10 37.0 

1140 

981.226 

— .352 

+ .088 

980.962 

981.015 

+ .053 

+ .045 

6. Scharfenstein, Germany. 

51 50.0 

10 36.0 

623 

981.229 

— .192 

-t- .041 

981.078 

981.130 

+ .052 

4- .044 

7. Naye, Switzerland. 

46 26.0 

6 58.7 

1987 

980.746 

— .613 

+ .074 

980.207 

980.233 

4- .026 

+ .018 

8. Villeneuve, Switzerland. 

46 24.1 

6 55.7 

376 

980.743 

— .116 

— .074 

980.553 

980.572 

+ .019 

+ .011 

9. Chaumont, Switzerland. 

47 01.4 

6.57.1 

1018 

980.799 

— .314 

4- .025 

980.510 

980.554 

+ .044 

+ .036 

10. Neuenburg (Neuchatel), Switzerland. 

47 00.1 

6 57.3 

487 

980.797 

— .150 

— .026 

980.621 

980.653 

+ .032 

+ .024 

11. Gornergrat, Switzerland. 

45 59.0 

7 46.8 

3016 

980.705 

— .931 

+ .165 

979.939 

979.992 

+ .053 

+ .045 

12. Riflelberg, Switzerland. 

45 59.6 

7 45.3 

2566 

980. 705 

— .792 

4- .122 

980.035 

980.090 

+ .055 

4- .047 

13. Zermatt, Switzerland. 

46 01.5 

7 45.0 

1603 

980.708 

— .495 

— .007 

980. 206 

980.250 

4- .044 

+ .036 

14. Belalp, Switzerland. 

46 22.9 

7 59.6 

2132 

980.741 

— .658 

4- .079 

980.162 

980.172 

+ .010 

+ .002 

15. Brig, Switzerland. 

46 19.7 

8 00.4 

683 

980.737 

— .211 

— .085 

980.441 

980.437 

— .004 

— .012 

16. Eggishorn, Switzerland. 

46 25.2 

8 06.8 

2187 

980.745 

— .675 

+ .086 

980.156 

980.169 

4- .013 

+ .005 

17. Fiesch, Switzerland. 

46 24.2 

8 08.1 

1049 

980.743 

— .324 

— .043 

980.376 

980.376 

.000 

— .008 

18. St. Maurice, Switzerland. 

46 13.0 

7 00.2 

422 

980.726 

— .130 

— .091 

980.505 

980.512 

+ .007 

— .001 

19. Honolulu, Hawaiian Islands «. 

21 18.1 

157 51.8 

6 

978. 711 

— .002 

4- .162 

978.871 

978.946 

+ .075 

4- .067 

20. Manna Kea, Hawaiian Islands a . 

19 49.2 

155 28.8 

3981 

978.623 

—1.229 

+ .469 

977.863 

978.069 

+ .206 

4- .198 

21. Hachinohe, Japan. 

40 31 

141 30 

21 

980.212 

— .006 

+ .049 

980.255 

980.359 

+ .104 

4- .096 

22. St. Georges, Bermuda a . 

32 21 

64 40 

2 

979.509 

— .001 

4- .218 

979.726 

979.806 

4- .080 

4- .072 

23. Jamestown, St. Helena a . 

-15 55 

5 43.7 

10 

978.418 

— .003 

+ .177 

978.592 

978. 712 

+ .120 

+ .112 

24. Sorvagen, Norway. 

67 53.6 

13 02 

19 

982.478 

— .006 

+ .016 

982.488 

982.622 

+ .134 

+ .126 

25. Kala-i-Chumb, Turkestan. 

38 27.3 

70 46.5 

1345 

980.029 

— .415 

— .086 

979.528 

979.462 

— .066 

— .074 

26. St. Paul Island, Alaska . 

57 07.3 

170 16.6 

10 

981.682 

— .003 

+ .041 

981.720 

981.726 

+ .006 

— .002 

27. St. Michael, Alaska a . 

63 28.5 

162 02.4 

1 

982.178 

.000 

— .004 

982.174 

982.192 

4- .018 

4- .010 

28. Sitten, Switzerland. 

46 14.1 

7 21.5 

514 

980.728 

— .159 

— .082 

980. 487 

980.480 

— .007 

— .015 

29. Visp, Switzerland. 

46 17.6 

7 53.0 

649 

980. 733 

— .200 

— .090 

980.443 

980.441 

— .002 

— .010 

30. Iselle, Switzerland. 

46 12.5 

8 12.1 

630 

980.725 

— . 194 

— .105 

9 SO. 426 

980.430 

4- .004 

— .004 

31. Gsteig, Switzerland. 

46 23.2 

7 16.2 

1185 

980.742 

— .366 

— .001 

980.375 

980.396 

4- .021 

+ .013 

32. Simplon Hospice, Switzerland. 

46 14.9 

8 01.9 

1998 

9SO.729 

— .617 

+ .076 

980.188 

980.202 

4- .014 

+ .006 

33. Grand St. Bernard, Switzerland. 

45 52.1 

7 10.4 

2473 

980.694 

— .763 

+ .131 

980.062 

9.80.072 

+ .010 

+ .002 

34. Sanetsch, Switzerland. 

46 19.3 

7 17.2 

2011 

980.736 

— .630 

+ .085 

980.191 

980.211 

-f -020 

4- .012 

35. Chanriori, Switzerland. 

45 56.3 

7 22.9 

2435 

980.700 

— .751 

+ .113 

980.062 

980.107 

+ .045 

+ .037 

36. Schwarzsee, Switzerland. 

45 59.5 

7 42.7 

2582 

980.705 

— .797 

-P .125 

980.033 

980.090 

4- .057 

+ .049 

37. Rome, Italy. 

41 53.5 

12 29.7 

49 

980.335 

— .015 

— .012 

980.308 

980.367 

4- .059 

+ .051 

38. Florence (Arcetri), Italy. 

43 45.2 

11 15.2 

184 

980.503 

— .057 

— .023 

980.423 

980.491 

+ .068 

4- .060 

39. Leghorn, Italy. 

43 32.0 

10 18.5 

6 

980.483 

— .002 

— .018 

980. 463 

980.534 

+ .071 

4 .063 

40. Genoa, Italy.'.. 

44 29.2 

8 55 

98 

980.569 

— .030 

— .029 

980.510 

980.557 

4- .047 

+ .039 


a This station is in west longitude. 






































































Chapter III.—COMPARISON OF APPARENT ANOMALIES AT STATIONS IN THE UNITED 
STATES BY THE HAYFORD AND OLD METHODS OF REDUCTION. 


In the following tables g 0 " — To and p 0 —7o have the same meanings as in the reports of 
the International Geodetic Association. 

The quantity g 0 " — To is the^ipparent anomaly when the Helmert formula of 1901 and the 
Bouguer reduction are used. The Bouguer formula has been very generally applied in 

2gH/ 35 

'= + - 4 -( 1 - 


) 


reducing pendulum observations to the level of the sea. This formula is dg = -r - V x ~ 4A 

where dg is the correction to observed gravity, g is gravity at sea level, H is elevation above 
sea level, r is radius of the earth, 5 is density of matter lying above sea level, and A is mean 
density of the earth. The first term takes account of the distance from the earth’s center, 
and the second term of the vertical attraction of the matter lying between sea level and the 
station, on the supposition that the latter is located on an indefinitely extended horizontal 
plain. Wherever the topography about a station departs materially from this conditon of a 
horizontal plain a third term must be added to the above formula, being a correction to the 
second term or to observed gravity on account of such irregularities. The Bouguer reduc¬ 
tion thus takes no account of isostatic compensation and neglects all curvature of the sea-level 
surface, the topography being treated as if it were standing on a plain of indefinite extent. 

The quantity g 0 — y 0 is the apparent anomaly when the Helmert formula of 1901 is used in 
connection with the so-called reduction to sea level in free air only (0.0003086 H ). This reduc¬ 
tion ignores both the topography and the isostatic compensation. It takes account simply of 
the increased distance of the station from the earth’s center when the station is above sea level. 

A comparison of the anomalies by the Hayford method, on the one hand, with those by the 
two older methods, as shown in the columns headed g 0 " — y Q , and g 0 — y 0 , on the other hand, will 
therefore show the merits of the Hayford method of reduction in compariosn with the Bouguer 
and the free-air methods. 

This comparison of the Hayford method with the Bouguer and free-air reductions is made 
because the Bouguer reduction postulates a total lack of compensation and a consequent high 
rigidity of the earth’s crust while the free-air method assumes that each piece of topography 
is completely compensated for at zero depth. Besides, the Bouguer and free-air methods are 
those which have been most generally used. 

The Hayford anomalies in the following table are based upon the Coast and Geodetic 
Survey formula of 1912 in which the first term is 978.038. 

58 



INVESTIGATIONS OF GRAVITY AND ISOSTASY 


59 


Number and name of station 


1. Key West, Fla. 

2. West Palm Beach, Fla. 

3. Punta Gorda, Fla. 

4. Apalachicola, Fla. 

5. New Orleans, La. 

6. Rayville, La. 

7. Galveston, Tex. 

8. Point Isabel, Tex. 

9. Laredo, Tex. 

10. Austin, Tex. (capitol). 

11. Austin, Tex. (university). 

12. McAlester, Okla. 

13. Little Rock, Ark. 

14. Columbia, Tenn. 

15. Atlanta, Ga. 

16. McCormick, S. C. 

17. Charleston, S. C. 

18. Beaufort, N. C. 

19. Charlottesville, Va. 

20. Deer Park, Md. 

21. Washington, D. C. (Coast and 

Geodetic Survey Office). 

22. Washington, D. C. (Smithson¬ 

ian Institution). 

23. Baltimore, Md. 

24. Philadelphia, Pa. 

25. Princeton, N. J. 

26. Hoboken, N. J. 

27. New York, N. Y. 

28. Worcester, Mass. 

29. Boston, Mass. 

30. Cambridge, Mass. 

31. Calais, Me. 

32. Ithaca, N. Y. 

33. Cleveland, Ohio. 

34. Cincinnati, Ohio. 

35. Terre Haute, Ind. 

36. Chicago, Ill. 

37. Madison, Wis. 

38. St. Louis, Mo. 

39. Kansas City, Mo. 

40. Ellsworth, Kans. 

41. Wallace, Kans. 

42. Colorado Springs, Colo. 

43. Pikes Peak, Colo. 

44. Denver, Colo. 

45. Gunnison, Colo. 

46. Grand Junction, Colo. 

47. Green River, Utah. 

48. Pleasant Valley Junction, Utah. 

49. Salt Lake City, Utah. 

50. Grand Canyon, Wyo. 

51. Norris Geyser Basin, Wyo. 

52. Lower Geyser Basin, Wyo. 

53. Seattle, Wash, (university). 

54. San Francisco, Cal. 

55. Mount Hamilton, Cal-.. 

56. Seattle, Wash, (high school) — 

57. Iron River, Mich. 

58. Ely, Minn. 

59. Pembina, N. Dak. 

60. Mitchell, S. Dak. 

61. Sweetwater, Tex. 

62. Kerrville, Tex. 

63. El Paso, Tex. 

64. Nogales, Ariz. 

65. Yuma, Ariz. 

66. Compton, Cal. 

67. Goldfield, Nev. 

68. Yavapai, Ariz. 

69. Grand Canyon, Ariz. 

70. Gallup, N. Mex. 

71. Las Vegas, N. Mex. 

72. Shamrock, Tex. 

73. Denison, Tex. 

74. Minneapolis, Minn. 

75. Lead, S. Dak. 


Anomalies by Hay ford, Bouguer, and free-air reductions. 


Number and name of station 


Anomaly 


Hayford, 

1912 


Bouguer 

(0o"-7o) 


In free air 

(Qo—T/o) 


Anomaly 


Hayford, 

1912 

Bouguer 

(S7o"-7o) 

In free air 
( 9o-7o) 

+0.005 

+0.048 

+0.048 

+ .018 

+ .057 

+ .057 

+ .010 

+ .038 

+ .038 

.000 

+ .023 

+ .023 

- .013 

+ .008 

+ .008 

+ .016 

+ .029 

+ .032 

— .009 

+ .006 

+ .006 

+ .027 

+ .049 

+ .050 

- .020 

- .022 

- .009 

- .008 

- .021 

- .003 

- .010 

- .023 

- .003 

- .027 

- .045 

- .018 

+ .030 

+ .030 

+ .039 

+ .020 

+ .017 

+ .040 

- .023 

- .036 

- .001 

+ .015 

+ .017 

+ .035 

- .021 

+ .003 

+ .003 

- .021 

+ .023 

+ .023 

- .013 

- .021 

- .003 

+ .010 

- .019 

+ .059 

+ .037 

+ .048 

+ .049 

+ .039 

+ .049 

+ .050 

- .011 

.000 

+ .003 

+ .022 

+ .037 

+ .039 

- .019 

- .004 

+ .002 

+ .024 

+ .039 

+ .040 

+ .022 

+ .037 

+ .041 

- .020 

— .014 

+ .006 

+ .005 

+ .024 

+ .026 

■+■ • 005 

+ .022 

+ .023 

- .008 

+ .006 

+ .010 

- .023 

- .033 

- .010 

- .003 

- .016 

+ .005 

- .019 

- .034 

- .009 

- .009 

- .016 

.000 

- .007 

- .012 

+ .008 

- .005 

- .024 

+ .006 

- .005 

- .014 

+ .004 

- .016 

- .038 

- .009 

+ .014 

- .029 

+ .016 

- .012 

- .105 

- .004 

- .007 

- .188 

- .006 

+ .021 

- .204 

+ .216 

- .016 

- .182 

- .023 

+ .020 

- .229 

+ .027 

+ .024 

- .158 

- .019 

- .021 

- .180 

- .056 

+ .004 

- .187 

+ .036 

+ .010 

- .146 

- .023 

- .002 

- .208 

+ .044 

+ .021 

- .177 

+ .060 

- .001 

- .193 

-j- . 035 

- .093 

- .111 

- .105 

- .023 

+ .019 

+ .030 

- .003 

+ .003 

+ .125 

- .093 

- .111 

- .103 

+ .038 

+ .009 

+ .060 

+ .023 

- .010 

+ .039 

+ .019 

- .008 

+ .018 

+ .001 

- .040 

+ .003 

- .029 

- .084 

- .012 

+ .031 

- .003 

+ .052 

+ .007 

- .111 

+ .016 

- .050 

- .132 

- .004 

+ .009 

+ .001 

+ .007 

- .050 

- .041 

- .042 

- .013 

- .166 

+ .022 

+ .001 

- .162 

+ .043 

- .010 

- .173 

- .098 

- .013 

- .211 

+ .009 

+ .003 

- .189 

+ .028 

+ .032 

- .031 

+ .047 

+ .005 

- .012 

+ .012 

+ .059 

+ .034 

+ .062 

+ .052 

- .072 

+ .104 


76. Bismarck, N. Dak. 

77. Hinsdale, Mont. 

78. Sandpoint, Idaho. 

79. Boise, Idaho. 

80. Astoria, Oreg. 

81. Sisson, Cal. 

82. Rock Springs, Wyo. 

83. Paxton, Nebr. 

84. Washington, D. C. (Bureau of 

Standards). 

85. North Hero, Vt. 

86. Lake Placid, N. Y. 

87. Potsdam, N. Y. 

88. Wilson, N. Y. 

89. Alpena, Mich. 

90. Virginia Beach, Va. 

91. Durham, N. C. 

92. Fernandina, Fla. 

93. Wilmer, Ala. 

94. Aliceville, Ala. 

95. New Madrid, Mo. 

96. Mena, Ark. 

97. Nacogdoches, Tex. 

98. Alpine, Tex. 

99. Farwell, Tex. 

100. Guymon, Okla. 

101. Helen wood, Tenn. 

102. Cloudiand, Tenn. 

103. Hughes, Tenn. 

104. Charleston, W. Va. 

105. State College, Pa. 

106. Fort Kent, Me. 

107. Prentice, Wis. 

108. Fergus Falls, Minn. 

109. Sheridan, Wyo. 

110. Boulder, Mont. 

111. Skykomish, Wash. 

112. Olympia, Wash. 

113. Heppner, Oreg. 

114. Truekee, Cal. 

115. Winnemueca, Nev. 

116. Ely, Nev. 

117. Guernsey, Wyo. 

118. Pierre, S. Dak. 

119. Fort Dodge, Iowa. 

120. Keithsburg, Ill. 

121. Grand Rapids, Mich. 

122. Angola, Ind. 

123. Albany, N. Y. 

124. Port Jervis, N. Y. 

125. Atlantic City, N. J. 

126. Bridgehampton, N. Y. 

127. Chatham, Mass. 

128. Rockland, Me. 

129. Lancaster, N.H. 

130. Whitehall, N. Y. 

131. Little Falls, N. Y. 

132. Watertown, N. Y. 

133. Southport, N. Y. 

134. Erie, Pa. 

135. Parkersburg, W. Va. 

136. Columbus. Ohio. 

137. Indianapolis, Ind. 

138. Springfield, Ill. 

139. Lebanon, Mo. 

140. Joplin, Mo. 

141. Fort Smith, Ark. 

142. Texarkana, Ark. 

143. Hot Springs, Ark. 

144. Alexandria, La. 

145. Laurel, Miss. 

146. Richmond, Va. 

147. Emporia, Va. 

148. Greenville, N. C. 

149. Wilmington, N. C. 

150. Cheraw, S. C. 


+0.002 

-0.052 

+0.005 

+ 

.029 

— 

.053 

+ 

.020 

4* 

.002 

— 

.105 


.034 

+ 

.008 

— 

.117 

— 

.026 

— 

.013 

+ 

.003 

+ 

.003 

_ 

.010 

_ 

.103 

+ 

.013 

+ 

.013 

— 

.191 

+ 

.020 

— 

.006 

— 

.099 

+ 

.004 

+ 

.037 

+ 

.046 

+ 

.057 

+ 

.001 

— 

.004 


.000 

+ 

.006 

_ 

.017 

+ 

.046 

+ 

.021 

+ 

.011 

+ 

.025 

— 

.010 


.014 

— 

.004 

— 

.020 

— 

.032 

— 

.012 

— 

.048 

— 

.015 

— 

.015 

+ 

.036 

+ 

.045 

+ 

.058 

+ 

.010 

+ 

.036 

+ 

.035 

— 

.044 

— 

.027 

— 

.018 

— 

.017 

— 

.010 

— 

.001 

+ 

.001 

O- 

.001 

+ 

.010 

_ 

.052 

_ 

.066 

_ 

.029 

— 

.012 

— 

.005 

+ 

.004 

+ 

.021 

— 

.088 

+ 

.002 

— 

.016 

— 

.132 

+ 

.003 

— 

.017 

— 

.110 

— 

.010 

+ 

.040 

+ 

.015 

+ 

.063 

+ 

.004 

— 

.042 

+ 

.142 

— 

.029 

— 

.074 

+ 

.032 

— 

.024 

— 

.045 

— 

.026 

— 

.021 

— 

.038 

— 

.003 

_ 

.013 

_ 

.021 

_ 

.004 

+ 

.024 

— 

.005 

+ 

.042 

— 

.006 

— 

.034 

+ 

.003 

+ 

.032 

— 

.116 

+ 

.009 

— 

.015 

— 

.181 

— 

.014 

_ 

.028 

_ 

.087 

_ 

.067 

+ 

.033 

+ 

.026 

+ 

.029 

— 

.027 

— 

.093 

— 

.026 

— 

.028 

— 

.162 

+ 

.037 

— 

.009 

— 

.150 

— 

.005 

_ 

.021 

_ 

.207 

+ 

.007 

+ 

.036 

— 

.113 

+ 

.028 

+ 

.014 

— 

.039 

+ 

.009 

+ 

.015 

— 

.011 

+ 

.025 

— 

.008 

— 

.018 

— 

.003 

+ 

.002 

_ 

.008 

+ 

.013 

+ 

.011 

— 

.001 

+ 

.030 

— 

.043 

— 

.048 

— 

.041 

— 

.033 

— 

.035 

— 

.022 

— 

.023 

+ 

.003 

+ 

.003 


.022 

+ 

.005 

+ 

.006 

— 

.014 

+ 

.018 

+ 

.018 

— 

.015 

+ 

.003 

+ 

.004 

— 

.018 

— 

.031 

— 

.003 

— 

.039 

— 

.047 

— 

.043 

_ 

.024' 

_ 

.038 

_ 

.023 

— 

.025 

— 

.032 

— 

.016 

— 

.030 

— 

.047 

— 

.018 

— 

.027 

— 

.040 

— 

.018 

— 

.024 

— 

.042 

— 

.022 

_ 

.012 

_ 

.028 

_ 

.003 

+ 

.001 

— 

.012 

+ 

.012 

— 

.016 

— 

.023 

— 

.003 

+ 

.011 

— 

.012 

+ 

.031 

+ 

.016 

— 

.009 

+ 

.025 

_ 

.016 

__ 

.030 

_ 

.015 

+ 

.011 

+ 

.009 

+ 

.020 

+ 

018 

+ 

.009 

+ 

.030 

— 

.006 

+ 

.008 

+ 

.011 

+ 

.014 

+ 

.025 

+ 

.033 

+ 

.003 

4- 

.018 

+ 

.021 

+ 

.013 

+ 

.032 

+ 

.036 

— 

.018 

+ 

.007 

+ 

.009 

— 

.031 

— 

.001 


.000 

+ 

.002 

+ 

.017 

+ 

.023 






































































































































































60 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 
Anomalies by Hayford, Bouguer, and free-air reductions —Continued. 


Number and name of station 


151. Charlotte, N. C. 

152. Asheville, N. C. 

153. Cleveland, Tenn. 

154. Winston-Salem, N. C.. 

155. Knoxville, Tenn. 

156. Bristol, Va. 

157. Homestead, Fla. 

158. Sebring, Fla. 

159. Titusville, Fla. 

160. Leesburg, Fla. 

161. Cedar Keys, Fla. 

162. Macon, Ga. 

163. Albany, Ga. 

164. Pensacola, Fla. 

165. Opelika, Ala. 

166. Huntsville, Ala. 

167. Arkansas City, Ark_ 

168. Memphis, Tenn. 

169. Mammotn Spring, Ark 

170. Hopkinsville, Ky. 

171. Danville, Ky. 

172. Clifton Forge, Va. 

173. Greenville, Ala. 

174. Birmingham, Ala. 

175. Lexington, Va. 

176. Prestonsburg, Ky. 

177. Traverse City, Mich... 

178. Seney, Mich. 

179. Oconto, Wis. 

180. Grand Rapids, Wis_ 

181. Winona, Minn. 

182. Baldwin, Wis. 

183. Cumberland, Wis. 

184. Cambridge, Minn. 

185. Brainerd, Minn.. 



Anomaly 




Anomaly 


Hayford, 

1912 

Bouguer 

(<7o"-7o) 

In free air 

(go To) 

Number and name of station 

Hayford, 

1912 

Bouguer 

(go" To) 

In free air 

(go To) 

+0.025 

+0.023 

+0.048 

186. Aberdeen, S. Dak. 

187. Faith, S. Dak. 

+0.012 

-0.029 

+0.015 

- .005 

- .045 

+ .029 

+ .015 

- .058 

+ .029 

- .023 

- .041 

- .013 

188. Marmartk, N. Dak. 

189. Towner, N. Dak. 

+ .035 

- .051 

+ .041 

- .038 

- .049 

- .018 

+ .032 

- .014 

+ .036 

- .021 

- .045 

- .014 

190. Crosby, N. Dak. 

+ .017 

- .041 

+ .026 

- .015 

- .052 

+ .005 

191. Crookston, Minn. 

+ .011 

- .016 

+ .013 

- .036 

+ .001 

+ .001 

192. Poplar, Mont. 

193. Miles City, Mont. 

+ .019 

- .050 

+ .018 

- .017 

+ .011 

+ .014 

+ .030 

- .061 

+ .018 

- .001 

+ .030 

+ .030 

194. Huntley, Mont. 

195. Lander, Wyo. 

+ .011 

- .105 

- .003 

- .014 

+ .012 

+ .015 

+ .019 

- .182 

- .001 

- .021 

+ .003 

+ .003 

196. Faribault, Minn. 

+ .036 

+ .011 

+ .044 

+ .019 

+ .023 

+ .034 

197. St. James, Minn. 

+ .006 

- .020 

+ .016 

+ .002 

+ .015 

+ .021 

198. Edgemont, S. Dak. 

199. Dawson, Minn. 

+ .054 

- .067 

+ .050 

- .014 

+ .008 

+ .008 

+ .017 

- .014 

+ .022 

- .026 

- .028 

- .001 

200. Cokato, Minn. 

+ .006 

- .019 

+ .017 

- .023 

- .034 

- .012 

201. Wasta, S. Dak. 

+ .030 

- .052 

+ .025 

- .012 

- .004 

+ .001 

202. Mooreroft, Wyo. 

+ .021 

- .109 

+ .034 

+ .013 

+ .015 

+ .023 

203. Duluth, Minn. 

204. Osage, Iowa. 

+ .050 

+ .025 

+ .048 

+ .013 

+ .002 

+ .019 

- .026 

- .050 

- .011 

+ .006 

+ .001 

+ .020 

205. Randolph, Nebr. 

+ .002 

- .042 

+ .015 

- .030 

- .034 

- .043 

- .065 

- .010 
- .029 

^ 206. Valentine, Nebr. 

+ .018 
- .029 

- .058 

+ .030 
- .024 

207. Wheeling, W. Va. 

- .047 

- .011 

- .001 

+ .013 

208. Leon, Iowa. 

- .008 

- .031 

+ .007 

- .033 

- .034 

- .014 

| 209. Laurel, Md. 

i 210. Harrisburg, Pa. 

+ .034 

+ .043 

+ .049 

- .024 

- .047 

- .011 

- .029 

- .031 

- .019 

- .024 

- .042 

- .020 

211. Pittsburg, Pa. 

- .023 

- .041 

- .015 

+ .001 

- .009 

+ .011 

212. Rockville, Md. 

+ .046 

+ .053 

+ .067 

+ .001 

- .008 

+ .016 

213. Upper Marlboro, Md. 

+ .013 

+ .027 

+ .028 

- .025 

- .038 

- .018 

! 214. Fairfax, Va. 

215. Crisfield, Md. 

+ .036 

+ .042 

+ .055 

- .042 

- .063 

- .029 

- .029 

- .002 

- .002 

+ .015 

- .006 

+ .017 

216. Fredericksburg, Va. 

+ .005 

+ .015 

+ .017 

- .050 

- .074 

- .036 

! 217. Dover, Del. 

- .010 

+ .010 

+ .011 

- .049 

- .074 

- .033 

218. North Tamarack, Mich. 

+ .031 

+ .019 

+ .059 

- .027 
+ .012 

- .051 

- .018 

- .017 
+ .023 

219. Hagerstown, Md. 

1 

- .049 

- .053 

- .035 


The mean values of the anomalies with and without regard to sign are shown in the follow¬ 
ing table: 



Anomaly 

Hayford, 

1912 

Bouguer 

In free 
air 

Mean with regard to sign 219 stations. 

-0.003 
.020 
- .002 
.019 

-0.037 
.050 
- .036 
.049 

+0.012 
.026 
+ .013 
.025 

Mean without regard to sign 219 stations. 

Mean with regard to sign 217 stations (Seattle stations omitted). 

Mean without regard to sign 217 stations (Seattle stations omitted). 


The mean without regard to sign is much larger by the free air and the Bouguer than the 
Hayford reductions and for the Bouguer it is so large as to show that the condition upon which 
it is based, namely, that of a rigid earth, is very far from the truth. 

There are only two Hayford anomalies greater than 0.059 dyne, and those are at Seattle, 
Wash., at stations so close together that they should be considered really only one station. 
The maximum free-air anomaly is at Pikes Peak, Colo. (No. 43), and is +0.216 dyne. The 
maximum Bouguer anomaly is —0.229 at Gunnison, Colo. (No. 45). 

The following table gives for the three methods the number of anomalies which fall within 
certain limits: 










































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


61 


Number of anomalies of different magnitudes. 


Limits of anomalies in dynes 

Number of anomalies 

Limits of anomalies in dynes 

Number of anomalies 

Hayford, 

1912 

Bouguer 

In free 
air 

Hayford, 

1912 

Bouguer 

In free 
air 

0.200 to 0.300. 

0 

5 

1 

0.050 to 0.060. 

8 

13 

11 

.100 to .200. 

0 

31 

5 

.040 to .050. 

8 

29 

18 

.090 to .100. 

2 

2 

1 

.030 to .040. 

28 

28 

25 

.080 to .090. 

0 

3 

0 

.020 to .030. 

54 

24 

40 

.070 to .080. 

0 

4 

0 

.010 to .020. 

69 

37 

52 

.060 to .070. 

0 

5 

7 

.000 to .010. 

50 

38 

59 










An inspection of the data in this table shows that the anomalies by the Hayford 1912 
method are distributed in fair agreement with the law of distribution of accidental errors. There 
is no indication of any decided systematic error for those anomalies. On the other hand, the 
distribution of the anomalies by each of the older methods of reduction departs greatly from the 
law of distribution of accidental errors and indicates that there are substantial systematic errors 
present. 

GRAVITY ANOMALY MAPS. 

The 1912 Hayford anomalies for the 219 stations in the United States and the 42 stations 
in Canada are shown in figure 11. The contours were drawn mechanically. The whole area 
covered by the stations was laid out in triangles, each triangle having as its apexes three contigu¬ 
ous stations. In all cases where there was a choice those stations were selected which gave most 
nearly an equiangular triangle. The points on the contours were determined by interpolations 
along the triangle sides between the stations at their ends. There are several places where sharp 
angles in the contours were taken out and the contours rounded, but these are of very minor 
importance. 

The map shows no relations between the anomalies and the topography except for coast 
topography, but it does seem to show some relation between the anomalies and the geologic 
formation. Along the coast where the geologic formation is generally Cenozoic the anomaly 
areas are mostly negative. The large area of Paleozoic formation which extends westward from 
Pennsvlvania is mostly negative, while the large Mesozoic and pre-Cambrian areas in the Dakotas, 
Minnesota, and in Montana and Wyoming tend to be positive. (See fig. 17.) 

Figure 15 shows the gravity anomaly contours in the vicinity of the District of Columbia. 
These are so intricate that they could not be shown well on the small scale of figure 11. 

Figure 12 shows the 1916 Hayford anomalies and the gravity contours for the 219 stations 
in the United States, and figure 16 the 1916 anomalies and contours for the area surrounding 
the District of Columbia. These two maps differ very little from figures 11 and 15 showing the 
1912 contours. 

Figure 13 shows the Bouguer anomalies at the 219 stations in the United States and the 
anomaly contours. Little comment is needed in regard to this map. It was constructed in 
the same way as the 1912 and 1916 Hayford anomaly maps. It shows in a very impressive 
manner the close relations between the Bouguer anomalies and the character of the topography. 

Figure 14 shows the free-air anomaly contours for the United States. This shows in a 
striking manner the relation between the free-air anomalies and the elevations of the stations. 

Figures 13 and 14 seem to prove conclusively that the earth’s crust is not rigid and also 
that it is not highly plastic. On the other hand, figures 11 and 12 for the Hayford anomalies 
prove that the condition of isostasy with the compensation distributed to a considerable depth is 
very near the truth. 































62 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

AGREEMENT AS TO POSITIVE AND NEGATIVE AREAS DEDUCED FROM GRAVITY AND FROM 

DEFLECTION DATA. 

Ill figure 18 are shown the 1912 Hayford anomalies for the 219 stations in the United States 
and the differences between the observed and the computed values of the deflection of the vertical 
at many astronomic stations used by Hayford. 0 There are also shown a number of ovals inclosing 
areas in each of which, according to Hayford, the density of the material in the earth’s crust 
is abnormal. They were drawn by him before any results of the gravity reductions were available. 

In some of these areas gravity stations have been established, and in no case is there a 
conflict in the sign of the area as indicated and the sign of the gravity anomaly. There are many 
of the gravity stations not within these positive and negative areas as shown on the illustation 
which agree with the deflections of the vertical in their locality. 

The two classes of data supplement each other and frequently give a rather definite idea 
as to the direction from the station of the area under which the cause of a deflection of the 
vertical is located. For instance, if an arrow in figure 18, which shows by its length the size of 
the unaccounted-for deflection, is close to a gravity station, the latter being in prolongation of 
the resultant deflection, the gravity anomaly by its sign will indicate whether the plumb line 
is attracted in the direction of the arrow or repelled from the opposite side. It may be said 
that the gravity and deflection data arc in general in close accord. 


° Supplemental Investigation in 1909 of the Figure of the Earth and Isostasy. 



Chapter IV.—RELATION BETWEEN THE GRAVITY ANOMALIES AND THE TOPOGRAPHY. 

A severe test of the reasonableness of a method of reduction of gravity stations is whether 
the anomalies are different in size and sign, on an average, for different characters of topography. 

There are given below five tables, for as many different characters of topography, which 
contain the anomalies by four methods of reduction. The first method may be called the 
Hayford, 1912. In this method isostasy is considered complete, and the compensation is 
assumed to be directly under the station and uniformly distributed to a depth of 113.7 km. 
The formula used in this method for computing the theoretical gravity at a station is 
what is called the United States Coast and Geodetic Survey 1912 formula, in which the 
gravity at the equator is given as 978.038 dynes. The reciprocal of the flattening is 1/298.2 (the 
Helmert value of 1901 ; see p. 113). The second method is similar to the first one, except that 
the depth of compensation is 60 km., and the formula used gives a value of gravity at the 
equator of 978.040 dynes. Each of these methods is based on the theory of isostasy. The 
values of the depth and the equatorial gravity used in the second method were derived from 
a solution of all the data in the United States, from which was obtained the United States Coast 
and Geodetic Survey 1916 formula for the United States. The derivation of this formula is 
given on page 123. 

The third method is the Bouguer, in which topography is considered, but the isostatic 
compensation is not. It postulates a rigid crust of the earth. The fourth method is the free 
air, in which neither the topography nor the compensation is taken into account. It postu¬ 
lates a very plastic crust with the compensation at zero depth. The Helmert formula of 1901 
was used in computing the theoretical gravity at the latitude of the stations for the Bouguer 
and the free-air methods. 

At the end of the five tables there is given a table of the mean anomalies with and without 
regard to sign. 

HAYFORD, BOUGUER, AND FREE-AIR ANOMALIES, ARRANGED IN GROUPS ACCORDING TO 

TOPOGRAPHY. 

Twenty-seven coast stations, in the order of their distances from the 1000-fathom line. 



Distance 
from 1000- 
fathom line 

Anomaly. 

Number and name of station 

Hayford, 
1912; depth, 
113.7 km 

Hayford, 
1916; depth, 
60.0 km 

Bouguer 

(9 o"-yo ) 

In free air 

(<7o-7o) 

54. San Francisco, Cal. 

Kilometers 

85 

-0.023 

-0.010 

+0.019 

+0.030 
+ .023 

18. Beaufort, N. d. 

95 

- .021 

- .008 

+ .023 

80. Astoria, Oreg. 

120 

- .013 

- .010 

+ .003 

-i- .003 
- .015 

90. Virginia. Beach, Va. 

130 

- .048 

- .039 

- .015 

92. Ferhandina, Fla. 

145 

+ .010 

+ .015 

+ .036 

+ .035 

1. Key West, Fla. 

150 

+ .005 

+ .015 

+ .048 

+ .048 

125. Atlantic City, N. J. 

160 

- .023 

— .018 

+ .003 

+ .003 

8. Point Isabel, Tex. 

160 

+ .027 

+ .030 

+ .049 

+ .050 

126. Bridgehampton, N. Y. 

180 

- .022 

- .016 

-i- .005 

+ .006 

215. Crisffeld, Mcl. 

185 

- .029 

- .023 

- .002 

- .002 

149. Wilmington, N. C. 

190 

- .031 

- .024 

- .001 

.000 

164. Pensacola, Fla. 

190 

- .014 

- .010 

+ .008 

+ .008 

127. Chatham, Mass. 

195 

- .014 

- .007 

+ .018 

+ .018 

5. New Orleans, La. 

210 

- .013 

- .010 

+ .008 

+ .008 

4. Apalachicola, Fla. 

225 

.000 

+ .004 

+ .023 

+ .023 

27. New York, N. Y. 

225 

+ .022 

+ .025 

+ .037 

+ .041 

26. Hoboken, N. J. 

230 


+ .027 

+ .039 

+ .040 

G6. Compton, Cal. 

230 

- .050 

- .049 

- .041 

- .042 

2. West Palm Beach, Fla. 

243 

+ .018 

+ .027 

+ .057 

+ .057 

161. Cedar Keys, Fla..".. 

260 

- .021 

- .016 

+ .003 

+ .003 

2. Pirntfl. Oorda, Fla. 

280 

+ .010 

+ .017 

+ .038 

+ .038 

29. Boston, Mass. 

300 

+ .005 

+ .008 

+ .024 

+ .026 

30. Cambridge, Mass. 

300 

+ .005 

+ .009 

+ .022 

+ .023 

17. Charleston, 7 S. C. 

305 

- .021 

- .016 

+ .003 

+ .003 

7. Galveston, Tex. 

330 

- .009 

- .008 

+ .006 

+ .006 

159. Titusville, Fla. 

330 

- .001 

+ .007 

+ .030 

+ .030 

128. Rockland, Me. 

350 

- .015 

- .013 

+ .003 

+ .004 








- .009 

- .003 

+ .017 

+ .017 



.018 

.017 

.021 

.022 




63 









































64 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 
Forty-six stations near the coast, in the order of their distances from the open coast. 


Number and name of station 


157. Homestead, Fla. 

31. Calais, Me. 

25. Princeton, N. J. 

93. Wilmer, Ala. 

217. Dover, Del. 

23. Baltimore, Md. 

28. Worcester, Mass. 

160. Leesburg, Fla. 

24. Philadelphia, Pa. 

124. Port Jervis, N. Y. 

158. Sebring, Fla. 

148. Greenville, N. C. 

81. Sisson, Cal. 

147. Emporia, Va. 

150. Cheraw, S. C. 

146. Richmond, Va. 

213. Upper Marlboro, Md. 

173. Greenville, Ala. 

209. Laurel, Md. 

21. Washington, D. C. (Coast and Geodetic Survey office) 

22. Washington, D. C. (Smithsonian Institution). 

163. Albany, Ga. 

145. Laurel, Miss. 

84. Washington, D. C. (Bureau of Standards). 

216. Fredericksburg, Va. 

144. Alexandria, La. 

212. Rockville, Md. 

214. Fairfax, Va. 

91. Durham, N. C. 

9. Laredo, Tex. 

65. Yuma, Ariz. 

97. Nacogdoches, Tex. 

123. Albany, N. Y. 

16. McCormick, S. C. 

10. Austin, Tex. (capitol). 

11. Austin, Tex. (university). 

19. Charlottesville, Va. 

151. Charlotte, N. C. 

219. Hagerstown, Md. 

162. Macon, Ga. 

165. Opelika, Ala. 

32. Ithaca, N. Y. 

94. Alieeville, Ala. 

62. Kerrville, Tex. 

106. Fort Kent, Me. 

6. Rayville, La. 

Mean with regard to sign. 

Mean without regard to sign. 




Anomaly 


Distance 
from the 
open coast 

Havford, 
1912; 
depth, 
113.7 km 

Hayford, 

1916; 

depth, 

60 km 

Bouguer 

(<7o"-To) 

In free air 

(0o~7o) 

Kilometers 

20 

-0.036 

-0.026 

4-0.001 

4-0.001 

50 

- .008 

- .007 

4- .006 

4- .010 

60 

- .019 

- .016 

- .004 

4- .002 

65 

- .044 

- .042 

- .027 

- .018 

65 

- .010 

- .006 

4- .010 

4- .011 

75 

- .011 

- .008 

.000 

4- .003 

85 

- .020 

- .015 

- .014 

4- .006 

85 

- .014 

- .008 

4- .012 

4- .015 

90 

4- .022 

4- .025 

4- .037 

4- .039 

100 

- .033 

- .027 

- .035 

- .022 

110 

- .017 

' - .010 

4- .011 

4- .014 

130 

- .018 

- .012 

4- .007 

4- .009 

142 

- .010 

4- .009 

- .103 

4- .013 

145 

+ .013 

4- .016 

4- .032 

4- .036 

150 

+ .002 

4- .005 

4- .017 

4- .023 

150 

4- .003 

4- .005 

4- .018 

4- .021 

150 

4- .013 

4- .016 

4- .027 

4- .028 

160 

- .011 

- .009 

- .001 

4- .013 

160 

4- .034 

4- .036 

4- .043 

4- .049 

170 

4- .037 

4- .038 

4- .048 

4- .049 

170 

4- .039 

4- .040 

4- .049 

4- .050 

170 

4- .002 

4- .005 

4- .015 

4- .021 

170 

4- .014 

4- .016 

4- .025 

4- .033 

175 

4- .037 

4- .039 

4- .046 

4- .057 

180 

4- .005 

4- .007 

4- .015 

+ .017 

190 

- .006 

- .005 

4- .008 

4- .011 

190 

4- .046 

4- .048 

4- .053 

4- .067 

200 

4- .036 

4- .037 

4- .042 

4- .055 

210 

4- .036 

4- .038 

4- .045 

4- .058 

215 

- .020 

- .022 

- .022 

- .009 

220 

4- .009 

4- .006 

+ .001 

4- .007 

220 

- .012 

- .013 

- .005 

4- .005 

220 

- .043 

- .041 

- .048 

- .041 

235 

4- .015 

4- .017 

4- .017 

4- .035 

245 

— .008 

- .008 

- .021 

- .003 

245 

- .010 

- .010 

- .023 

- .003 

250 

- .013 

- .011 

- .021 

- .003 

250 

4- .025 

4- .029 

4- .023 

4- .048 

250 

- .049 

— .046 

- .053 

- .035 

265 

4- .019 

4- .021 

4- .023 

4- .034 

265 

- .026 

- .020 

- .028 

- .001 

305 

- .023 

— .020 

- .033 

- .010 

305 

- .017 

- .017 

- .010 

- .001 

310 

4- .031 

4- .035 

- .003 

4- .052 

315 

- .013 

- .014 

- .021 

- .004 

325 

4- .016 

4- .017 

4- .029 

4- .032 


- .001 

4- .002 

4- .004 

4- .017 


.021 

.020 

.025 

.023 


Eighty-eight stations in the interior and not in mountainous regions, arranged in the order of elevation. 





Anomaly. 


Number and name of station 

Elevation 

Hayford, 
1912; deptn, 
113.7 km 

Hayford, 
1916; depth, 
60 km 

Bouguer 

(0o"-Yo) 

In free air 

(do— To) 

167. Arkansas City, Ark. 

Meters 

44 

-0.012 

-0.012 

-0.004 

4-0.001 

95. New Madrid, Mo. 

79 

4- .001 

- .002 

4- -001 

4- .010 

168. Memphis, Tenn. •. . 

88. Wilson N. Y. 

80 

4- .013 

4- .012 

4- .015 

4- .023 

87 

- .010 

- .013 

- .014 

- .004 

13. Little Rock, Ark. 

89 

4- .030 

4- .027 

4- .030 

4- .039 

142. Texarkana, Ark. 

99 

4- .011 

4- .009 

4- .009 

4- .020 

87. Potsdam, N. Y. 

130 

4- .021 

4- .021 

4- .011 

4- .025 

141. Fort Smith, Ark. 

135 

- .016 

- .018 

- .030 

- .015 

132. Watertown, N. Y. 

147 

- .025 

- .024 

- .032 

- .016 

35. Terre Haute, Ind. 

151 

- .009 

- .010 

- .016 

.000 

38. St. Louis, Mo... 

154 

- .005 

- .007 

- .014 

4- .004 

169. Mammoth Spring, Ark. 

156 

4- .013 

4- .013 

4- .002 

+ .019 

120. Keithsburg, Ill. 

170. Hopkinsville, Ky. 

167 

- .008 

- .008 

- .018 

- .003 

176 

4- .006 

4- .007 

4- .001 

4- .020 

89. Alpena, Mich. 

178 

- .020 

- .019 

- .032 

- .012 

























































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


65 


Eighty-eight stations in the interior and not in mountainous regions, arranged in the order of elevation —Continued. 


» 


Number and name of station 


174. Birmingham, Ala. 

177. Traverse City, Mich. 

179. Oconto, Wis. 

36. Chicago, Ill. 

138. Springfield, Ill. 

104. Charleston, W. Va. 

135. Parkersburg, W. Va. 

143. Hot Springs, Ark. 

134. Erie, Pa. 

166. Huntsville, Ala. 

181. Winona, Minn. 

207. Wheeling, W. Va. 

14. Columbia, Tenn. 

33. Cleveland, Ohio. 

203. Duluth, Minn. 

137. Indianapolis, Ind. 

178. Seney, Mich. 

73. Denison, Tex. 

136. Columbus, Ohio. 

211. Pittsburg, Pa. 

121. Grand Rapids, Mich. 

12. McAlester, Okla. 

59. Pembina. N. Dak. 

34. Cincinnati, Ohio. 

74. Minneapolis, Minn. 

191. Crookston, N. Dak. 

133. Southport, N. Y. 

37. Madison, Wis. 

39. Kansas City, Mo. 

154. Winston-Salem, N. C. 

171. Danville, Ky. 

196. Faribault, Minn. 

140. Joplin, Mo. 

184. Cambridge, Minn. 

180. Grand Rapids, Wis. 

122. Angola, Ind. 

200. Cokato, Minn. 

199. Dawson, Minn. 

15. Atlanta, Ga. 

197. St. James, Minn. 

119. Fort Dodge, Iowa. 

182. Baldwin, Wis. 

208. Leon, Iowa. 

204. Osage, Iowa. 

108. Fergus Falls, Minn. 

185. Brainerd, Minn. 

96. Mena, Ark. 

218. North Tamarack, Mich. 

183. Cumberland, Wis. 

139. Lebanon, Mo. 

186. Aberdeen, S. Dak. 

60. Mitchell, S. Dak. 

58. Ely, Minn. 

189. Towner, N. Dak. 

118. Pierre, S. Dak. 

57. Iron River, Mich. 

40. Ellsworth, Kans. 

107. Prentice, Wis. 

205. Randolph, Nebr. 

76. Bismarck, N. Dak. 

190. Crosby, N. Dak..— 

192. Poplar, Mont. 

61. Sweetwater, Tex. 

77. Hinsdale, Mont. 

72. Shamrock, Tex. 

193. Miles City, Mont. 

206. Valentine, Nebr. 

187. Faith, S. Dak. 

188. Marmarth, N. Dak. 

83. Paxton, Nebr. 

100. Guymon, Okla. 

41. Wallace, Kans. 

99. Farwell, Tex. 

Mean with regard to sign.... 
Mean without regard to sign 




Anomaly 


Elevation 

Hayford, 
1912; depth, 
113.7 km 

Hayford, 
1916; depth, 
60 km 

Bouguer 

(0o"-7o) 

In free air 
(9o—7o) 

Meters 

179 

-0.033 

-0.030 

-0.034 

-0.014 

180 

-f .001 

.000 

- .009 

4- .011 

181 

- .025 

- .027 

- .038 

- .018 

182 

- .007 

- .009 

- .012 

+ .008 

183 

- .016 

I-', 
r—t 

o 

1 

- .023 

- .003 

184 

- .024 

- .024 

- .045 

- .026 

185 

- .024 

- .023 

- .042 

- .022 

190 

+ .018 

4- .018 

4- .009 

+ .030 

198 

- .027 

- .027 

- .040 

- .018 

200 

- .023 

- .021 

- .034 

- .012 

201 

+ .015 

+ .015 

- .006 

+ .017 

205 

- .029 

- .026 

- .047 

- .024 

207 

+ .026 

+ .028 

+ .017 

+ .040 

210 

- .003 

- .003 

- .016 

4- .005 

216 

+ .050 

+ .049 

+ .025 

4- .048 

217 

+ .001 

+ .002 

- .012 

4- .012 

223 

+ .001 

+ .002 

- .008 

4- .016 

230 

+ .005 

+ .004 

— .012 

4- .012 

231 

- .012 

- .011 

- .028 

- .003 

235 

- .023 

- .022 

- .041 

- .015 

236 

+ .002 

+ .002 

- .008 

+ .013 

240 

- .027 

- .028 

- .045 

- .018 

243 

+ .019 

+ .015 

- .008 

4- .018 

245 

- .019 

- .019 

- .034 

- .009 

256 

+ .059 

+ .057 

+ .034 

+ .062 

260 

+ .011 

+ .008 

- .016 

+ .013 

266 

- .030 

- .024 

- .047 

- .018 

270 

- .005 

- .005 

- .024 

+ .006 

278 

- .016 

- .018 

- .038 

- .009 

284 

- .038 

- .034 

- .049 

- .018 

300 

- .030 

- .026 

- .043 

- .010 

301 

+ .036 

+ .035 

+ .011 

+ .044 

303 

+ .016 

+ .016 

- .009 

+ .025 

303 

- .027 

- .028 

- .051 

- .017 

306 

- .042 

- .042 

- .063 

- .029 

318 

+ .011 

+ .012 

- .001 

4- .030 

319 

+ .006 

-f* . 005 

- .019 

+ .017 

323 

-F .017 

+ .015 

- .014 

+ .022 

324 

- .023 

- .021 

- .036 

- .001 

330 

+ .006 

+ .005 

- .020 

4- .016 

340 

+ .015 

+ .013 

- .011 

+ .025 

342 

- .050 

- .051 

- .074 

- .036 

344 

- .008 

- .008 

- .031 

4- .007 

356 

- .026 

- .025 

- .050 

- .011 

366 

- .006 

- .008 

- .034 

4- .003 

367 

+ .012 

+ .012 

- .018 

4- .023 

368 

— .052 

- .051 

— .066 

- .029 

370 

+ .031 

+ .031 

4- .019 

+ .059 

380 

- .049 

- .048 

- .074 

- .033 

385 

+ .011 

+ .012 

- .012 

+ .031 

396 

+ .012 

+ .009 

- .029 

+ .015 

408 

+ .001 

- .003 

- .040 

4- .003 

448 

+ .023 

+ .023 

- .010 

+ .039 

451 

+ .032 

+ .030 

- .014 

+ .036 

454 

+ .014 

+ .009 

- .039 

4- .009 

458 

+ .038 

+ .041 

4- .009 

+ .060 

469 

+ .014 

+ .012 

- .029 

+ .016 

469 

4- .024 

+ .026 

- .005 

4- .042 

515 

+ .002 

.000 

- .042 

4- .015 

516 

+ .002 

.000 

- .052 

4- .005 

598 

+ .017 

+ .015 

- .041 

4- .026 

608 

+ .019 

4- .015 

- .050 

+ .018 

655 

- .029 

- .028 

- .084 

- .012 

661 

+ .029 

4- .024 

- .053 

+ .020 

708 

+ .032 

4- .034 

- .031 

+ .047 

718 

+ .030 

+ .028 

- .061 

4- .018 

785 

+ .018 

+ .020 

- .058 

+ .030 

786 

+ .015 

+ .014 

- .058 

4- .029 

822 

+ .035 

+ .036 

- .051 

+ .041 

932 

- .006 

- .005 

- .099 

+ .004 

949 

- .017 

- .016 

- .110 

- .010 

1005 

- .012 

- .009 

- .105 

- .004 

1259 

- .016 

- .013 

- .132 

4- .003 


- .001 

- .001 

- .028 

4- .009 


.019 

.019 

.033 

.020 


59387°—17-5 




































































































66 IT. S. COAST AND GEODETIC STJBVEY SPECIAL PUBLICATION NO. 40. 


Thirty-six stations in mountainous regions and below the general level, arranged in the order of their distances below the 

general level. 


Number and name of station 

Average 
elevation 
within 
100 miles 
of station 
minus 
elevation 
of station 

Elevation 
of station 

Havford, 
1912; 
depth, 
113.7 km 

Ano 

Hayford, 

1916; 

depth, 

60 km 

maly 

Bouguer 

(?o"-7o) 

In free air 
(ffo — yo) 


Meters 

Meters 





70. Gallup, N. Mex. 

30 

1990 

-0.013 

-0.001 

-0.211 

+0.009 

156. Bristol, Va. 

32 

514 

- .015 

- .007 

- .052 

4- .005 

105. State College, Pa. 

33 

358 

- .021 

- .017 

- .038 

- .003 

202. Moorcroft, Wyo. 

52 

1295 

+ .021 

4- .024 

- .109 

+ .034 

67. Goldfield, Nev. 

112 

1716 

- .013 

- .001 

- .166 

4- .022 

153. Cleveland, Tenn. 

123 

263 

- .023 

- .020 

- .041 

- .013 

210. Harrisburg, Pa. 

125 

104 

- .029 

- .027 

- .031 

- .019 

175. Lexington, Va. 

126 

324 

- .024 

- .019 

- .047 

- .011 

172. Clifton Forge, Va. 

157 

325 

- .034 

- .027 

- .065 

— .029 

85. North Hero, Vt. 

167 

35 

4- .001 

- .002 

- .004 

.000 

176. Prestonsburg, Ky. 

180 

193 

- .024 

- .022 

- .042 

- .020 

131. Little Falls, N. V. 

198 

137 

- .024 

- .021 

- .038 

- .023 

155. Knoxville, Tenn. 

200 

2S0 

- .021 

- .019 

- .045 

— .014 

201. Wasta, S. Dak. 

201 

706 

4- .030 

4- .026 

- .052 

4- .025 

63. El Paso, Tex. 

205 

1146 

+ .007 

+ .010 

- .111 

4- .016 

198. Edgemont, S. Dak. 

208 

1066 

+ .054 

-f • 0o4 

- .067 

4- .050 

113. Heppner, Oreg. 

264 

598 

- .027 

- .030 

- .093 

- .026 

130. Whitehall, N. Y. 

290 

38 

- .039 

- .037 

- .047 

- .043 

112. Olympia, Wash. 

306 

19 

4- .033 

4- .029 

4- .026 

4- .029 

110. Boulder, Mont. 

307 

1493 

- .015 

- .006 

- .181 

- .014 

111. Skykomish. Wash. 

322 

280 

- .028 

- .019 

- .087 

- .067 

117. Guernsey, Wyo. 

324 

1322 

4- .036 

+ .035 

- .113 

4- .028 

115. Winnemucca, Nev. 

316 

1311 

- .009 

- .006 

- .150 

- .005 

109. Sheridan, Wyo. 

378 

1150 

4- .032 

+ .035 

- .116 

4- .009 

82. Rock Springs, Wyo. 

379 

1910 

+ .013 

4- .020 

- .191 

4- .020 

45. Gunnison, Colo. 

380 

2340 

+ .020 

4- .037 

- .229 

4- .027 

194. Huntley, Mont. 

385 

919 

4- .011 

4- .007 

- .105 

- .003 

42. Colorado Springs, Colo. 

420 

1841 

- .007 

+ .003 

- .188 

- .006 

195. Lander, Wyo. 

536 

1635 

4- .019 

4- .024 

- .182 

- .001 

49. Salt Lake City, Utah. 

570 

1322 

+ .010 

+ .011 

- .146 

- .023 

44. Denver, Colo. 

574 

1638 

- .016 

- .016 

- .182 

- .023 

79. Boise, Idaho. 

575 

821 

4- .008 

+ .002 

- .117 

- .026 

78. Sandpoint, Idaho. 

588 

637 

4- .002 

.000 

- .105 

- .034 

69. Grand Canyon, Ariz. 

824 

849 

- .010 

- .001 

- .173 

- .098 

46. Grand Junction, Colo. 

850 

1398 

+ .024 

4- .024 

- .158 

- .019 

47. Green River, Utah. 

870 

1243 

- .021 

- .026 

- .180 

- .056 

Mean with regard to sign. 



- .003 

.000 

- .107 

- .008 

Mean without regard to sign. 



.020 

.018 

.108 

.024 


Twenty stations in mountainous regions and above the general level, arranged in the order of their distances above the general 

level. 


Number and name of station 

Eleva¬ 
tion of 
station 
minus 
average 
elevation 
within 
100 miles 

Eleva¬ 
tion of 
station 

Anomaly 

Hayford, 
1912; 
depth, 
113.7 km 

Hayford, 

1916; 

depth, 

60 km 

Bouguer 
{go"— yo) 

In free 
air 

(go—yo) 


Meters. 

Meters. 





129. Lancaster, N. H. 

1 

261 

-0.018 

-0.011 

-0.031 

—0.003 

71. Las Vegas, N. Mex. 

18 

1960 

4- .003 

4- .016 

- .189 

4- .028 

116. Ely, Nev. 

19 

1962 

- .021 

- .003 

- .207 

4- .007 

101. Helenwood, Tenn. 

33 

422 

4- .040 

4- .045 

4- .015 

4- .063 

52. Lower Geyser Basin, Wyo. 

63 

2200 

- .001 

4- .015 

- .193 

4- .035 

51. Norris Gevser Basin, Wvo. 

139 

2276 

4- .021 

4- .038 

- .177 

4- .060 

48. Pleasant Valley Junction. Utah. 

147 

2191 

4- .004 

4- .021 

- .187 

4- .036 

152. Asheville, N. C. 

180 

670 

- .005 

4- .009 

- .045 

4- .029 

50. Grand Canyon, Wyo. 

249 

2386 

- .002 

4- .017 

- .208 

4- .044 

98. Alpine, Tex. 

265 

1359 

4- .021 

4- .034 

- .088 

4- .062 

64. Nogales, Ariz. 

288 

1181 

- .050 

- .040 

- .132 

- .004 

20. Deer Park, Md. 

291 

770 

4- .010 

4- .022 

- .019 

4- .059 

86. Lake Placid, N. Y. 

306 

571 

4- .006 

4- .016 

- .017 

4- .046 

103. Hughes, Tenn. 

427 

994 

- .029 

- .012 

- .074 

4- .032 

75. Lead, S. Dak. 

468 

1590 

4- .052 

4- .062 

- .072 

4- .104 

68. Yavapai, Ariz. 

512 

2179 

4- .001 

4- .012 

- .162 

4- .043 

114. Truckee, Cal. 

512 

1805 

- .028 

.000 

- .162 

4- .037 

55. Mount Hamilton, Cal. 

1202 

1282 

- .003 

4- .013 

4- .003 

4- .125 

102. Cloudland, Tenn. 

1324 

1890 

4- .004 

4- .021 

- .042 

4- .142 

43. Pikes Peak, Colo. 

2035 

4293 

4- .021 

4- .045 

- .204 

4- .216 

Mean with regard to sign. 



4- .001 

-f .016 

— .110 

-f- . OdS 

Mean without regard to sign. 



.017 

.022 

.111 

.059 




































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


67 


Mean anomalies. 


WITH REGARD TO SIGN. 



Number 
of stations 

Mean anomaly. 

Hayford, 
1912; 
depth, 
113.7 km 

Hayford, 

1916; 

depth, 

60 km 

Bouguer 

In free air 

Coast stations. 

27 

46 

88 

36 

20 

217 

-0.009 
- .001 
- .001 

- .003 
4- .001 

- .002 

-0.003 
+ .002 
- .001 
.000 
+ .016 
+ .001 

+0.017 
+ .004 
- .028 

- .107 

- .110 
- .036 

+0.017 
+ .017 
+ .009 
- .008 
+ .058 
+ .013 

Stations near the coast. 

Stations in the interior, not in mountainous regions.... 

Stations in mountainous regions, below the general level. 

Stations in mountainous regions, above the general level. 

All stations (except the two Seattle stations). 

WITHOUT REGARD TO SIGN. 

Coast stations. 

Stations near the coast. 

Stations in the interior, not in mountainous regions. 

Stations in mountainous regions, below the general level. 

Stations in mountainous regions, above the general level. 

All stations (except the two Seattle stations). 

27 

46 

88 

36 

20 

217 

0.018 

.021 

.019 

.020 

.017 

.019 

0.012 

.020 

.019 

.018 

.022 

.019 

0.021 

.025 

.033 

.108 

.111 

.049 

0.022 

.023 

.020 

.024 

.059 

.025 

Anomalies for all stations treated as a single group. 


Anomaly 

Hayford, 
1912; 
depth, 
113.7 km 

Hayford, 

1916; 

depth, 

60 km 

| 

Bouguer 

In free air 

Mean with regard to sign, 219 stations. 

-0.003 
.020 
- .002 
.019 

0.000 
.020 
+ .001 
.019 

-0.037 
.050 
- .036 
.049 

+0.012 
.026 
+ .013 
.025 

Mean without regard to sign, 219 stations. 

Mean with regard to sign, 217 stations (Seattle stations omitted). 

Mean without regard to sign, 217 stations (Seattle stations omitted). 


The mean anomalies with regard to sign for the Bouguer reduction show a remarkable 
range in values from +0.017 dyne for the coast stations to —0.110 dyne for stations in 
mountainous regions which are above the general level. The other classes of topography have 
mean Bouguer values which fall between these extremes. The value which is nearest zero is 
for the stations near but not on the coast; that is, on the coastal plains. The effect of ignoring 
the compensation here should have little effect as the topography is in general very low. We 
may conclude that there are decided relations between the Bouguer anomalies and the character 
of the topography. Therefore it is certain that the earth’s crust is not rigid with the oceans 
and continents held in place as a result of its rigidity. The Bouguer method is certainly not 
based upon correct principles. 

The free-air anomalies have means with regard to sign for the five topographic groups 
which range from —0.008 for mountain stations below the general level to +0.058 for those 
mountain stations which are above the general level. The coast stations and those near but 
not on the coasts have mean anomalies, with sign considered, of +0.017. The stations in the 
interior not in mountain regions have a mean of +0.009. If the mean of the 1912 and 1916 
values for the gravity at the equator, which is 0.009 dyne greater than the Helmert 1901 value, 
had been used, the mean of the anomalies by the free-air method for the stations in the interior 
and not in mountainous regions would have been zero. This is as one might expect, for the 
effects of the distant topography and compensation are not large (see tables on pp. 20 to 48) 
and the effect of the near topography on a plain is almost exactly balanced by the isostatic 
compensation. It is a fact which should be kept in mind when studying the effect of topography 
and isostatic compensation that the attractive effect of a mass of uniform density, of great 
horizontal extent, and of a uniform thickness is the same as for a mass of a much greater thick¬ 
ness, with a correspondingly smaller density and the same great horizontal extent. As an 



































































68 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


example, a disk of material 100 feet thick of density 2.67 and 1000 miles in horizontal radius 
will have practically the same attraction as a mass 100 000 feet thick with a density of 0.00267 
and as before 1000 miles in horizontal dimensions from the center of the disk. Therefore we 
have the attractive effect of the topography of a plain of great dimensions exactly or nearly 
balanced by the effect of the compensation. (See p. 72.) 

The mean of the 1912 Hayford anomalies with regard to sign is only —0.002 (omitting the 
Seattle stations) and the mean value for each of the five topographic groups is small except one. 
The mean of the coast station anomalies is — 0.009. This mean anomaly may be explained in 
part by the fact that nearly all the material along the coasts belongs to the Cenozoic or recent 
formation, and authorities give its density as ranging from 2.40 to 2.50. (See table on p. 215 of 
“The Strength of the Earth’s Crust” by Joseph Barrell in Volume XXII of Journal of Geology.) 
This material is no doubt of considerable thickness at many parts of the coasts. It is shown 
on pages 70 to 83 under the heading ‘ ‘Relation between the gravity anomalies and the geologic for¬ 
mation ” that the presence of light material in the earth’s crust near a station would tend to make 
the computed value of gravity too great and the difference between the observed and com¬ 
puted values would tend to be negative. If we should eliminate from consideration the coast 
stations or assume that the value — 0.009 is explained by the presence of the Cenozoic material, 
then the mean with regard to sign of the anomalies for the various topographic groups is 
never more than 0.003 dyne from the mean for all stations, and three of the groups have means 
which are only 0.001 from the mean of all. The total range in the means with regard to sign 
for the various groups, ignoring coast stations, is only 0.004 dyne. This is very different from 
the range in the means for the Bouguer and the free-air anomalies. It shows that this method 
is very much closer to the truth. 

The means for the Hayford 1912 anomalies for the various groups without regard to sign 
vary only slightly. The lowest is 0.017 for mountain stations above the general level, and the 
largest is 0.021 for stations near but not on the coast. The mean for all is 0.019. The mean 
of the Bouguer anomalies without regard to sign for the several groups varies from 0.021 for 
coast stations to 0.111 for stations in mountainous regions above the general level, while the 
free-air anomalies vary from 0.022 at coast stations to 0.059 at stations in mountainous 
regions above the general level. 

We must conclude that the average size of the anomalies without regard to sign indicates 
that there is no relation between the Hayford 1912 anomalies and the topography. 

The Hayford 1916 anomalies give substantially the same evidence in favor of isostasy that 
is given by the 1912 anomalies, but it is difficult to see which method of reduction is nearer 
the truth. 

The mean value for the 1916 anomalies with regard to sign for 217 stations is +0.001. 
The mean anomaly for the coast stations is —0.003, which is different from the mean by 0.004. 
For the 1912 anomalies the mean coast anomaly differs 0.007 from the mean of all, which is 
— 0.002. This may be considered as being in favor of a depth of 60 km. as against the depth of 113.7 
km. But, as stated above, and also on pages 76 and 77, the material near the coast belongs in gen¬ 
eral to the Cenozoic geologic formation which is less dense than normal (2.67). The presence of this 
less dense material makes the computed value of gravity too great and the anomalies negative. 
The effect of reducing the depth of compensation to 60 km. is to give the compensation of the 
oceans less effect at the coast stations, the computed gravity is less, and the negative anomalies 
are reduced in size on an average. It is questionable whether the reduced size of the mean 
anomaly with regard to sign for the 1916 reduction is evidence in favor of the reduced depth of 
compensation. 

The means with regard to sign for the 1916 anomalies in the groups near the coast, in 
the interior not in the mountainous regions, and in mountainous regions below the general 
level, are practically the same as for the 1912 anomalies. Hence there is little evidence from 
these in favor of either reduction. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


69 


There is a decided difference between the mean with regard to sign for the 1912 and 1916 
anomalies at stations in mountainous regions above the general level. The former is only 
+ 0.001, which shows no systematic error, while the latter is +0.016, which, on the other 
hand, shows a great systematic error. 

The change in depth from 113.7 km. to 60 km. does not make a material difference in the 
effect of the compensation for the stations in mountainous regions below the general level if 
there is local compensation of the mountain masses. (See p. 108.) The table of individual 
values for the anomalies on page 66 shows that for this class of topography the anomalies are 
nearly the same for the 1912 and the 1916 reductions. 

The table on page 66 for stations above the general level in mountainous regions shows 
that there is little or no similarity between the anomalies by the 1912 and 1916 methods. For 
the first method there are 9 stations of the 20 with negative anomalies, while for the latter 
there are only 4. There are only 3 of the 1912 anomalies above 0.030, while there are 6 of the 
1916 anomalies. 

If there is local compensation, then the effect of reducing the depth is to make the effect 
(negative) of the compensation greater and the computed value of gravity at a mountainous 
station less. The sign of the anomaly would in consequence tend to be positive. This is what 
we find to be the case. If the compensation is regional, then the effect of changing the depth 
of compensation is smaller than if the compensation were local. 

It is believed that from the above evidence the conclusion may be drawn that the depth 
of 113.7 km. is nearer the truth than 60 km. in mountainous regions, and that local distribution 
of the compensation is more probable than the regional if the latter distribution extends to great 
distances from the topographic features. This agrees with the evidence given under the heading 
“Regional versus local distribution of compensation.” (See pp. 85 to 92.) The data and 
discussion on pages 97 to 131 in comiection with the anomalies for various depths should be 
considered in connection with the data given above. 

It is believed that the further conclusions may be justified, that there is a relation between 
the coast topography and the gravity anomalies by the 1912 reduction, this relation probably 
being due to the lighter material in the earth’s crust below sea level, and that there is also a rela¬ 
tion between the topography and the gravity anomalies at stations in mountainous regions 
above the general level for the 1916 method, this relation being explained by the erroneous 
depth of compensation for this method (60 km.). 


Chapter V.—RELATION BETWEEN THE GRAVITY ANOMALIES AND THE GEOLOGIC 

FORMATION. 


Surface densities are known to differ somewhat from the mean surface density and these 
differences will sometimes occur over large areas. They should cause, therefore, some varia¬ 
tion of the value of the intensity of gravity from the normal. As the surface densities vary 
somewhat for the different geologic formations, a study was made to learn whether there is any 
relation between the Hayford gravity anomalies and the surface geology at the stations. On 
page 215 of the Journal of Geology (Vol. XXII, 1914) Barrell gives the following estimated 
mean specific gravities of geologic formations: 


Pre-Cambrian. 2. 75-2. 80 

Paleozoic and Mesozoic. 2. 50-2. 00 

Cenozoic. 2.40-2. 50 


The author presents the data in the tables following, which may be used as the basis for 
investigation by others who are interested in this subject. The tables give data for the 219 
stations in the United States, 42 stations in Canada, and 73 stations in India. For all of these 
stations the 1912 Hayford anomalies have been computed and are given. 

The stations in the United States and in Canada were plotted on the geologic map of 
North America which bears the following title: “Geologic map of North America, compiled 
by the United States Geological Survey in cooperation with the Geological Surve} 7- of Canada 
and Instituto Geologico de Mexico, under the supervision of Bailey Willis and George W. Stose, 
Scale 1:5 000 000, 1911.” The decision as to the surface geologic formation on which the sta¬ 
tions are located was based entirely on this map. It is probable that the classification would 
differ occasionally if other sources of information were used. The writer believes, however, 
that only minor changes would be made in the tables given below and the conclusions drawn 
from them would not be materially changed. 

The Indian stations were plotted on a geologic map taken from the pocket at the back of 
“A manual of the geology of India,” by Medlicott and Blanford, second edition, revised by 
Oldham, superintendent Geological Survey of India, 1893. 

The tables give the stations and the Hayford 1912 anomalies for each of the formations, 
(1) pre-Cambrian, (2) Paleozoic, (3) Mesozoic, (4) Cenozoic, (5) Effusive and Intrusive, and (6) 
unclassified. 

In the tables for the United States the 1912 and 1916 Hayford anomalies are given. The 
former are based upon the United States Coast and Geodetic Survey formula of 1912, viz, 

To = 978.038 (1+0.005302 sin 2 <£-0.000007 sin 3 2 <£) 

which gives the value of gravity for any latitude at sea level. The compensation was assumed 
to be uniformly distributed and complete at a depth of 113.7 km. The 1916 values are based 
upon the United States Coast and Geodetic Survey formula of 1916 (see p. — of this volume) 
viz, 

7 0 = 978.040 (1+0.005302 sin 2 <£-0.000007 sin 2 2<£) 

and upon a depth of isostatic compensation of 60 km. 

The relations between the gravity anomalies and the geologic formations in Canada and 
India are considered later (pp. 80 to 82). The anomalies given for these countries are compar¬ 
able with those shown in the following table for the 1912 formula and depth of compensation. 
It will be shown later in what measure the relations for the stations in those countries confirm 
or negative those in the United States. 

70 





INVESTIGATIONS OF GRAVITY AND ISOSTASY. 7l 

RELATION BETWEEN THE GRAVITY ANOMALIES AND THE GEOLOGIC FORMATION FOR STATIONS 

IN THE UNITED STATES. 

Stations in the United States and Hay ford anomalies for specified formations. 


Formation and station 

Hayford anomaly 

number 

1912 

1916 

Pre-Cambrian formation: 



16. 

+0.015 

+ 0.017 

24. 

+ .022 

+ .025 

43. 

+ .021 

+ .045 

45. 

+ .020 

+ .037 

57. 

+ .038 

+ .0-11 

58. 

+ .023 

+ .023 

75. 

+ .052 

+ .062 

102. 

+ .004 

+ .021 

107. 

+ .024 

+ .026 

152. 

- .005 

+ .009 

165. 

- .026 

- .020 

185. 

+ .012 

+ .012 

191. 

+ .011 

+ .008 

203. 

+ .050 

+ .049 

Paleozoic formation: 



12. 

- .027 

- .028 

14. 

+ .026 

+ .028 

20. 

+ .010 

+ .022 

29. 

+ .005 

+ .008 

30. 

+ .005 

+ .009 

32. 

- .023 

- .020 

33. 

- .003 

- .003 

34. 

- .019 

- .019 

35. 

- .009 

- .010 

36. 

- .007 

- .009 

37. 

- .005 

- .005 

38. 

- .005 

- .007 

39. 

- .016 

- .018 

59. 

+ .019 

+ .015 

61. 

- .029 

- .028 

72. 

+ .032 

+ .034 

74. 

+ .059 

+ .057 

78. 

+ .002 

. 000 

85. 

+ .001 

- .002 

88. 

- .010 

- .013 

89. 

- .020 

- .019 

96. 

- .052 

- .051 

101. 

+ .040 

+ .045 

104. 

- .024 

- .024 

105. 

- .021 

- .017 

106. 

- .013 

- .014 

119. 

+ .015 

+ .013 

120. 

- .008 

- .008 

121. 

+ .002 

+ .002 

122. 

+ .011 

+ .012 

123. 

- .043 

- .041 

124. 

- .033 

- .027 

128. 

- .015 

- .013 

129. 

- .018 

- .011 

130. 

- .039 

- .037 

131. 

- .024 

- .021 

132. 

- .025 

- .024 

133. 

- .030 

- .024 

134. 

- .027 

- .027 

135. 

- .024 

- .023 

136. 

- .012 

- .011 

137. 

+ .001 

+ .002 

138. 

- .016 

- .017 

139. 

+ .011 

+ .012 

140. 

+ .016 

+ .016 

141. 

- .016 

- .018 

143. 

+ .018 

+ .018 

153. 

- .023 

- .020 

155. 

- .021 

- .019 

156. 

- .015 

- .007 

166. 

- .023 

- .021 

169. 

+ .013 

+ .013 

170. 

+ .006 

+ .007 

171. 

- .030 

- .026 

172. 

- .034 

- .027 

174. 

- .033 

- .030 

175. 

- .024 

- .019 

176. 

- .024 

- .022 

177. 

+ .001 

.000 

178. 

+ .001 

+ .002 


Hayford anomaly 


Hayford anomaly 


number 

i 

1912 

1916 

number 

1912 

1916 

Paleozoic formation—Con. 

H 


Cenozoic formation—Con. 



179. 

-0.025 

-0.027 

93. 

—0.044 

—0.042 

181. 

+ .015 

+ .015 

95. 

+ .001 

— .002 

182. 

- .050 

- .051 

97. 

— .012 

— .013 

183. 

- .049 

- .048 

99. 

— .016 

— .013 

184. 

- .027 

- .028 

100. 

— .017 

— .016 

196. 

+ .036 

+ .035 

109 a. 

+ .032 

+ .035 

204. 

- .026 

- .025 

112. 

+ .033 

+ .029 

207. 

- .029 

- .026 

115. 

— .009 

— .006 

208. 

- .008 

- .008 

117o. 

+ .036 

+ .035 

210. 

- .029 

- .027 

125. 

— .023 

— .018 

211. 

- .023 

— .022 

126. 

- .022 

- .016 

219. 

- .049 

- .046 

127. 

- .014 

— .007 




142. 

+ .011 

+ .009 

Mesozoic formation: 



144. 

- .006 

- .005 

10. 

- .008 

— .008 

145. 

+ .014 

+ .016 

11. 

- .010 

- .010 


23. 

— .011 

— .008 

148. 

— .018 

- .012 

25.... 

- .019 

— .016 

149. 

- .031 

— .024 

40... 

+ .014 

+ .012 

157. 

— .036 

— .026 


158. 

- .017 

- .010 

42. 

- .007 

+ .003 

159. 

— .001 

+ .007 

4t>. 

+ .024 

-i- .024 




47... 

— .021 

— .026 

160. 

- .014 

- .008 

54... 

— .023 

— .010 

161. 

- .021 

— .016 

55. 

— .003 

+ .013 

163. 

+ .002 

+ .005 



164. 

- .014 

- .010 

60.... 

+ .001 

- .003 

167. 

- .012 

- .012 

62. 

+ .031 

+ .035 




70. 

- .013 

— .001 

168. 

+ .013 

+ .012 

71... 

+ .003 

+ .016 

190. 

+ .017 

+ .015 

73. 

+ .005 

+ .004 

206. 

+ .018 

+ .020 



213. 

+ .013 

+ .016 

77... 

+ .029 

+ .024 

215. 

— .029 

- .023 

91... 

+ .036 

+ .038 

217. 

— .010 

- .006 

94. 

- .017 

- .017 




108. 

- .006 

- .008 

Intrusive formation: 



118.. 

+ .014 

+ .009 

28. 

- .020 

- .015 



31. 

- .008 

- .007 

150. 

+ .002 

+ .005 

86. 

+ .006 

+ .016 

162.. 

+ .019 

+ .021 

103. 

- .029 

- .012 

186. 

+ .012 

+ .009 




187. 

+ .015 

+ .014 

Ill. 

- .028 

- .019 

188. 

+ .035 

+ .036 

151. 

+ .025 

+ .029 



154. 

- .038 

- .034 

189. 

+ .032 

+ .030 




192. 

+ .019 

+ .015 

Effusive formation: 



193 

+ .030 

+ .028 

50. 

- .002 

+ .017 

194.. 

+ .011 

+ .007 

51. 

+ .021 

+ .038 

195... 

+ .019 

+ .024 

52. 

- .001 

+ .015 


81. 

- .010 

+ .009 

197. 

+ .006 

+ .005 




198 . 

+ .054 

+ .0.54 

98. 

+ .021 

+ .034 

200 . 

+ .006 

+ .005 

no. 

- .015 

- .006 

201 

+ .030 

+ .026 

113. 

- .027 

- .030 

202 . 

+ .021 

+ .024 

114. 

- .028 

.000 

216. 

+ .005 

+ .007 







Unclassified: 



Cenozoic formation: 



13. 

+ .030 

+ .027 

1. 

+ .005 

+ .015 

15. 

- .023 

- .021 

2 . 

+ .018 

+ .027 

19. 

- .013 

- .011 

3 . 

+ .010 

+ .017 

21. 

+ .037 

+ .038 

4 . 

.000 

+ .004 

22. 

+ .039 

+ .040 

5. 

- .013 

- .010 







26. 

+ .024 

+ .027 

6 . 

+ .016 

+ .017 

27. 

+ .022 

+ .025 

7 . 

— .009 

— .008 

41. 

— .012 

- .009 

$ 

+ .027 

+ .030 

48. 

+ .004 

+ .021 

q . 

— .020 

— .022 

49. 

+ .010 

+ .011 

17. 

- .021 

- .016 







67. 

- .013 

- .001 

18 . 

- .021 

— .008 

68. 

+ .001 

+ .012 

44 . 

— .016 

- .016 

69. 

- .010 

- .001 

53 

J- - .093 

84. 

+ .037 

+ .039 

56 

— .100 

87. 

+ .021 

+ .021 

63. 

+ .007 

+ .010 







116. 

- .021 

- .003 

64 

— .050 

- .040 

146. 

+ .003 

+ .005 


+ .009 

+ .006 

147. 

+ .013 

+ .016 

66 

- .050 

- .049 

173. 

- .011 

- .009 

76 

+ .002 

.000 

180. 

- .042 

- .042 


+ .008 

+ .002 







199. 

+ .017 

+ .015 

80 

- .013 

- .010 

205. 

+ .002 

.000 

82 

+ .013 

+ .020 

209. 

+ .034 

, + .036 

83 

— .006 

— .005 

212. 

+ .046 

+ .048 

an 

— .048 

- .039 

214. 

+ .036 

+ .037 

Q2 

+ .010 

+ .015 

218. 

+ .031 

+ .031 








a These stations are near pre-Cambrian formations, 













































































































































































































































































72 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Stations in the United States and Hay ford anomalies for specified formations —Continued. 

SUMMARY. 

4 


Geologic formation 

♦ 

Number of stations 

Mean anomaly 

With plus 
anomalies 

With minus 
anomalies 

All 

With regard 
to sign 

Without regard 
to sign 

1912 

1916 

1912 

1916 

1912 

1916 

1912 

1916 

Pre-Cambrian. 

12 

13 

2 

1 

14 

+0.019 

+0.025 

0.023 

0.028 

Paleozoic. 

23 

20 

49 

50 

72 

- .011 

- .010 

.021 

.020 

Mesozoic. 

25 

26 

11 

10 

36 

+ .009 

+ .011 

.017 

.017 

Cenozoico. 

22 

22 

32 

32 

55 

- .007 

- .004 

.019 

.018 

Cenozoicb. 

22 

22 

31 

31 

54 

- .006 

- .003 

.018 

.016 

Intrusive. 

2 

2 

5 

5 

7 

- .013 

- .006 

.022 

.019 

Effusive. 

2 

5 

6 

2 

8 

- .005 

+ .010 

. 015 

.019 

Unclassified. 

18 

17 

8 

8 

26 

+ .010 

+ .014 

.021 

.021 

All stationso. 

104 

105 

113 

108 

218 

- .002 

.000 

.020 

.019 

All stations b . 

104 

105 

112 

107 

217 

- .002 

+ .001 

.019 

.019 


<* Counting the two Seattle stations as one. 
b With Seattle stations omitted. 


ANOMALIES ON PRE-CAMBRIAN FORMATIONS. 

In the above summary it is seen that there are 14 stations located on pre-Cambrian forma¬ 
tions and that 12 have positive and only 2 negative 1912 anomalies. For the 1916 anomalies 13 
are positive and only 1 negative. This seems to be very strong evidence that we may expect 
positive anomalies at much the greater number of future stations in the United States which 
may be located on the pre-Cambrian formation. It is noteworthy that nearly all of the pre- 
Cambrian stations in the United States are located on very small areas of that formation. 
This may give some clew as to the cause of the large positive anomaly. 

If the density of the upper strata of the earth’s crust for large distances (horizontal) from 
the stations is above normal, then the effect of this greater density, which will tend to increase 
the gravity, will be offset by the opposite effect of the compensating deficiency of density in the 
deeper crust. This is due to the fact that the effect of a certain amount of material in the form 
of a disk of infinite horizontal extent is the same on a unit mass of matter whether the unit mass 
is immediately above the surface of the attracting matter or at an indefinite distance above it. 
Therefore, if we should have a stratum or mass of pre-Cambrian material of density 2.90 at the 
earth’s surface directly under the station, and of great or infinite extent horizontally, it would 
have the same attractive effect on the unit mass as if this matter were distributed through a 
great vertical distance but had the same horizontal extent. Therefore, if the dense material 
at the surface were compensated for by a deficiency of density in the lower crust, the positive 
effect of the former would be exactly counterbalanced by the negative effect of the compensation. 
Hence, we should not expect a decided positive anomaly at a pre-Cambrian gravity station should 
the formation be of uniform thickness and of great horizontal dimensions. This statement is 
based upon the assumption, which may be substantially true, that the area in question is in a 
state of perfect isostatic equilibrium at the depth of compensation. 

If, however, the area of denser material is limited in horizontal extent, then the effect of the 
added material, being inversely proportional to the square of its distance from the attracted 
unit mass, will be greater than the negative effect of the compensation. Therefore, if there is a 
compensating lack of density in the lower crust, the resultant effect will be positive and we 
should have a positive gravity anomaly. The size of the anomaly will depend upon the thick¬ 
ness of tfie stratum of pre-Cambrian rock, its density, its horizontal extent, and the vertical 
location of the compensation. 

In Special Publication No. 10 (pp. 110 and 111) there are given some numerical examples 
showing the effect of strata of various thicknesses and densities. 

It should be borne in mind that in making the gravity reductions no numerical values are 
given for the densities in the earth’s crust below sea level. (See p. 8.) It is assumed that the 






































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


73 


densities in the crust under the coastal plane at sea level for the various strata are normal, and 
that these densities are modified by the isostatic compensation under the topography of the 
interior of the continents and under the oceans. It is only the deviations from the normal 
densities in the crust below sea level which are considered in these investigations. 

The effect of masses in different locations with reference to the station is indicated in the 
following table, which, with some additions, is reprinted from page 109 of Special Publication 
No. 10: 

Table of attractions for various masses. 

[Each tabular value is the vertical attraction in dynes produced at a station by a mass equivalent to a stratum 100 feet thick, of density 2.67, and of 
the horizontal extent indicated in the left-hand argument, if that mass is uniformly distributed from the level of the station down to the depth 
indicated in the top argument and from the station in all directions horizontally to the distance indicated in the left-hand argument.) 


Radius of mass 

• 

Depth 

1000 

feet. 

5000 

feet. 

10 000 
feet. 

15 000 
feet. 

113.7 

kilo¬ 

meters. 

1.2S km. (the outer radius of zone E). 

0.0030 

.0033 

.0034 

.0037 

.0040 

0.0018 

.0029 

.0032 

.0034 

.0037 

0.0011 

.0025 

.0029 

.0034 

.0037 

0.0008 

.0021 

.0027 

.0034 

.0037 

0.0000 

.0001 

.0003 

.0024 

.0035 

5 km..7.1.. 

10 km. 

166.7 km. (the outer radius of zone O). 

1190 km. (or 10° 44', the outer radius of zone 10;. 


It is seen from the preceding table that a pre-Cambrian formation 10 000 feet thick, with 
a density of 2.94 (just 10 per cent greater than the assumed normal surface density of 2.67) and 
10 km. in horizontal extent in all directions from a station on its surface will give an increase in 
gravity of 0.029 dyne. The effect of the isostatic compensation (uniformly distributed to the 
depth of compensation), the negative equivalent of 1000 feet of material of normal density 
(2.67), is only 0.003 dyne. The resultant effect is +0.026 dyne, approximately the average 
size of the 1912 pre-Cambrian anomaly. 

If we should have a pre-Cambrian formation 10 000 feet thick of density 2.94, as above, 
but of 166.7 km. horizontal extent in all directions from the station, the effect of the topography 
on gravity would be increased by 0.034 dyne, while the effect of the compensation of this excess 
of mass would be —0.024 dyne, and the resultant effect would be only +0.010 dyne. Now, 
if the foundation under consideration were extended horizontally 1190 km. from the station, 
the positive effect would be +0.037 dyne and the effect of its compensation —0.035 dyne, 
and the resultant effect at the station only +0.002 dyne. 

On page 80, under the discussion of the Canadian stations, it is shown that the anomalies 
at the stations in pre-Cambrian formations are not positive as in the United States. They 
differ little from the mean of all stations. The pre-Cambrian formations in Canada are of con¬ 
siderable horizontal extent, and therefore the effect of the increased surface densities is offset 
by the isostatic compensation. This agrees with the above reasoning. 

If there were many gravity stations on and near a limited area of pre-Cambrian formation, it 
might be possible to estimate from the results the approximate limits of the space within which 
the densities were above normal. But it must be borne in mind that the problem of determin¬ 
ing exactly the space or spaces within which there are abnormal densities which might cause 
the anomalies is not susceptible of mathematical solution. This is because there are too many 
unknowns which would enter into any equations used and arbitrary assumptions would have 
to be made. Of course, the problem can be treated mathematically and with greater numbers 
of stations in any given area the truth can be more closely approximated. 

It seems to be evident that the anomalies are not due simply to an assumed erroneous density 
of the mass above sea level, for at a number of pre-Cambrian stations the elevation above sea 
level is less than 1500 feet, and the maximum effect of a change in the density of 10 per cent in 
that mass would be only 0.005 dyne. The cause of the anomaly must therefore be located to a 
large extent below sea level in nearly all cases. 




















74 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


It is no doubt true that the deep-seated rocks have densities comparable with those of 
the pre-Cambrian rocks seen at the surface, but the cause of the anomaly at pre-Cambrian sta¬ 
tions seems to be due largely to the dense rock protruding through the materials of the upper 
crust which are of less density. 

The author does not mean to state that the whole of any anomaly is due to the geological 
formation, for there is probably in many cases a local lack of perfect isostasy which may pro¬ 
duce deviations from the normal gravity. 

It is a noteworthy fact that the pre-Cambrian stations in the United States show an excess 
of gravity in general, and that they are on areas which have been subjected to erosive action 
for geologic ages. We may conclude that as erosion has taken place there has been a rising 
of the areas due probably to isostatic adjustment. 

The 1916 anomalies, based upon a depth of compensation of only 60 km., are very little 
different from the 1912 anomalies, which are based upon a depth of 113.7 km. The former 
are, on an average, 0.006 dyne greater than the latter, and this is what might be expected 
upon the assumption of local perfect compensation. The fact that the compensation is closer 
to the station would make its effect greater, consequently the combined effect of the greater 
density of material above sea level and the compensating deficiency of material in the lower 
crust would be smaller than for the 1912 anomalies. 

The effect of a change in the depth of compensation is discussed on pages 97 to 131. 

ANOMALIES ON PALEOZOIC FORMATIONS. 

In the United States there are 72 stations in the Paleozoic formation, for which 49 of the 
1912 anomalies are negative and 23 positive. The mean with regard to sign is —0.011 dyne, 
and the mean without regard to sign is 0.021 dyne. 

The addition of 94 stations in the United States since the investigation in 1912 (Special 
Publication No. 12) has increased the tendency of the Paleozoic anomalies to be negative. 
A large area of the United States is covered by rock of this formation, and the 72 Paleozoic 
stations are nearly one-third of all the stations. 

The density of the Paleozoic formations is given by Barrell as 2.50 to 2.60. The average 
density, 2.55, is 0.12, or about 5 per cent, lower than the density used in making the computa¬ 
tions. The situation here is opposite to that connected with the pre-Cambrian formation, for 
the stations there tended to have positive anomalies. It might be assumed that the crust 
under the Paleozoic formation is not in a state of perfect isostasy, and that the anomalies are 
the result of the departure from that state. This view is probably erroneous, because the 
anomalies on very large areas of Paleozoic formation have negative values and would there¬ 
fore indicate decided regional deviation from the perfect condition. Most of the data contained 
in this report, including the anomaly maps, indicate that we have in the United States local 
rather than regional deviations from perfect isostasy. 

The tendency of the anomalies to be negative could be caused by the lower density of 
the material in this formation, as compared with the value used in the computations. If near 
a station in a Paleozoic area the density of the upper crust were below normal, say, 5 per cent, 
to a depth of 15 000 feet and to a horizontal distance of 10 km. from the station, the effect 
of this deficient density would be a change in the attraction of 0.020 dyne. The effect of the 
compensating increase in density in the lower crust would be +0.002. The combined effect 
of considering the local densities makes a difference of 0.018 in the anomaly at the station 
in question. 

The effect on gravity at a station due to using an erroneous value of the density of the 
topography, that is the material which is above sea level, would be small as a general rule for the 
average elevation of the Paleozoic stations in the United States is somewhat less than 1000 
feet. The effect of changing by 5 per cent the density of the topography to a depth of 1000 
feet and 10 km. in all directions from the stations would be only 0.0017 dyne. The effect of 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


75 


the compensation of the excess of mass would be less than 0.0002 dyne. It is evident that the 
principal cause of the negative Paleozoic anomalies is lower than sea level in the earth’s crust. 

It is probably true that the lighter density of Paleozoic material is the principal cause of 
the tendency for the anomalies at stations on this formation to have negative signs. This is 
no doubt supplemented by local departures from perfect isostasy near stations with large anomalies. 

It is possible that the positive anomalies and the small negative anomalies are in areas 
where the Paleozoic strata are thin or which have material denser than normal underlying 
the Paleozoic matter. 

The 1916 anomalies for Paleozoic areas seldom differ from the 1912 anomalies more than 
two units in the last place and the mean anomalies with and without regard to sign are practically 
the same. This is as might be expected, for the Paleozoic stations are in general on low topog¬ 
raphy and, as shown on page 72 in the discussion of the pre-Cambrian stations, a disk of very 
great horizontal extent has the same attractive effect regardless of the distance of the attracted 
mass from the surface of the disk. In fact, the effect of the topography and its compensation 
are so nearly equal at stations in Paleozoic areas that the anomalies by the free-air reduction, 
in which no account is taken of the topography and compensation, are nearly the same as the 
Hayford anomalies. An erroneous depth of compensation used in the computation can not 
explain the anomalies in the Paleozoic formation. 

That there is in general a close approximation to perfect isostasy is shown by the Bouguer 
anomalies in the interior of the continent not in mountainous regions, for they are nearly all 
negative and are of considerable size, while the algebraic mean of the Hayford anomalies is 
nearly zero. 

The Paleozoic negative anomalies in general are probably due in most part to departures 
from normal densities in the strata in the upper crust, but below sea level, comparatively 
near the station, and to a less degree to local departures from perfect isostasy. 

ANOMALIES ON MESOZOIC FORMATIONS. 

Of the 36 stations in the Mesozoic formation, 25 have positive and 11 negative 1912 anom¬ 
alies. The means with and without regard to sign are respectively +0.009 and 0.017 dyne. 

Barrell gives the density of Mesozoic rock as ranging from 2.50 to 2.60. This is lower than 
the density (2.67) used in making the topographic reductions. There seems to be no evident 
relation between the surface densities of the Mesozoic rocks and the anomalies. If there were 
the anomalies would be negative rather than positive. 

That there is some relation between the formation and the anomalies seems to be well 
established, for the positive anomalies largely exceed the negative ones in number, and the mean 
anomaly with regard to sign is just one-half the size of the mean of all (219) anomalies with¬ 
out regard to sign. But the cause of the positive sign of the Mesozoic anomalies is below the 
upper strata. That it is regional to a certain extent is shown by the persistency of the sign in 
any extensive Mesozoic formation, such as in the Dakotas and in eastern Montana. But that it 
varies from place to place is indicated by the different values of the anomaly. For instance, at 
Edgemont, S. Dak. (station No. 198) the anomaly is +0.054 dyne and at Moorcroft, Wvo. 
(station No. 202) only 90 miles distant, it is +0.021 dyne. 

There, of course, may be departures in the Mesozoic areas from the state of perfect isostasy, 
but it is impossible with the present data to determine with any degree of certainty what por¬ 
tion of an anomaly is due to such departures and what is caused by departures from normal 
densities in the crust above the depth of compensation or even below that depth. The depth of 
compensation as computed from geodetic data should not be considered as very definite. The 
probable error of the determination is comparatively large. The change in the deflection and 
the gravity anomalies is comparatively slow with a change of depth and the value of the depth 
is therefore somewhat indeterminate. (See pp. 97 to 112.) 


76 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


ANOMALIES ON CENOZOIC FORMATIONS. 

The anomalies at Cenozoic stations have a tendency to be negative, as is shown by an 
inspection of the anomalies at 55 Cenozoic stations in the United States. Only 22 of them 
are positive, while 32 are negative. 

Barrcll gives the Cenozoic densities as ranging from 2.40 to 2.50 (see table onp. 70), which 
is less than the density used in making the topographic reductions. That a portion of the 
anomalies is due to the small density of the surface material and of the crust close to the surface 
seems to be evident. The size of the anomalies may be an indication of the space occupied by 
the lighter material. Where the anomaly is large and negative the light strata would probably 
be of great thickness and of small horizontal dimensions. The erroneous density could be the 
cause of the negative anomalies, provided there were no local departure from perfect isostasy. 

If the Cenozoic formation of small density is small in horizontal dimensions, and if there is 
perfect local isostasy, the effect of the light material in the upper crust and near the surface 
would be much greater than the opposite effect of the compensating increase in density in the 
lower crust. 

For instance, if the density of the upper crust to a depth of 10 000 feet is 2.40 (10 per cent 
less than the assumed surface density), and if the material extends in a horizontal direction 10 lan. 
from the station, the effect would be — 0.029 dyne. The effect of the compensating increase in 
density in the remainder of the crust to the depth of the compensation would be only + 0.003 
d}me and the combined effect would be —0.026 dyne. If the lighter material extends 20 or 30 
km. from the station, the combined effect would be somewhat less, while if it extended 166.7 
km. in all directions from the station, the combined effect would be only —0.010 dyne. 

The cause of the large Cenozoic anomalies must be local, for there are decided differences 
in the size of the anomalies at pairs of stations which are comparatively close together. For 
instance, at Virginia Beach (station No. 90) the anomaly is —0.048 dyne, while at Crisfield 
(station No. 215) the anomaly is only —0.029 dyne. The distance between the stations is 
about 80 miles. 

It appears from the evidence above that we may gain from the negative anomalies of the 
Cenozoic formations some idea of the depth of the Cenozoic material at a station, and where there 
are many stations in any given locality of Cenozoic formation we may get an approximation to the 
horizontal limits of the affected spaces. For instance, it is reasonable to conclude that if the 
Virginia Beach anomaly is caused by a thick stratum of material of light density, and that if 
this stratum extends to Crisfield, it is considerably thinner at the latter station. The reasoning 
employed in the discussion of the pre-Cambrian anomalies on pages 72 to 74 would indicate that 
the large Cenozoic anomalies must be due largely to local causes, if it is assumed that an area 
under investigation is in a state of perfect isostatic equilibrium. 

The data in the table on page 63 indicate that there is strong evidence that the coast 
stations tend to have negative anomalies. In the table given on page 79 there are shown the 
anomalies at the Cenozoic stations back from the coast. Of the 19 stations there are 8 with 
positive and 11 with negative 1912 anomalies, but the mean anomaly with regard to sign is 
— 0.009 dyne. If, however, we eliminate the Seattle anomaly, which is — 0.093, and the anomaly 
of station 93 (Wilmcr, Ala.), which is —0.044 dyne, there would be 8 positive and 9 negative 
anomalies and the mean with regard to sign would be only —0.001 dyne. 

This is practically normal on an average. It may indicate that the Cenozoic material in 
the interior of the country is not of great thickness, or that, if thick, it is of considerable hori¬ 
zontal extent, or that the materials under the Cenozoic stratum have densities which are greater 
than the normal. Of course, the anomaly may in part be caused by a lack of perfect compen¬ 
sation. The Bouguer anomalies at the 17 stations under consideration indicate that there is 
considerable isostatic compensation under these stations. 

There is evidently a definite relation between the coasts and the gravity anomaly, but 
it may be due to the presence of Cenozoic materials which extend along practically all of the 
coasts. The cause of the difference in the size of the anomalies at different stations may be 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 77 

due to the varying thickness of the material and the varying horizontal dimensions of thick 
and thin strata. 

That the Cenozoic areas are undercompensated, as the negative anomalies might indicate, 
does not seem to be true, for the reason that these areas are areas of deposition in recent times 
and the areas have probably been sinking during the time when materials were accumulating 
on them. This deposition of material would lead one to suppose that the crust under such 
areas is heavier than normal. Undercompensation therefore appears to be improbable. The 
writer is aware that there may be even in areas of heavy deposition sections which are under¬ 
compensated, but this would be due to conditions existing before deposition began. 

The 1916 anomalies at Cenozoic stations show greater differences from the 1912 anomalies 
than they do for the other formations considered above. In most cases, where there are decided 
differences, the stations are on or near the coasts near where there is deep water. The com¬ 
puted effect, which is positive at a land station, of the compensation under the w^ater is greater 
when it is farther from the surface, for the effect of lengthening the distance to the effective 
center of the attracting mass is more than offset by the increase in the sine of the angle of 
depression to the effective center. The effect of a mass in the earth’s crust on the attracted 
unit mass is directly proportional to the sine of the angle of depression to the effective center 
of the attracting mass and inversely proportional to the square of the distance. 

The coast stations would therefore have a smaller computed gravity with the depth of 60 
km. than with a depth of 113.7 km. Consequently the negative anomalies would be reduced 
in size and the positive anomalies increased. For the coast stations the new depth (60 km.) 
gives a mean anomaly with regard to sign of —0.003 dyne, while with a depth of 113.7 km. 
the mean is —0.009 dyne. The new mean is nearer zero, but it is uncertain whether this is 
an indication that the smaller depth is nearer the truth. The discussion above shows that the 
negative anomalies based on the old depth may be accounted for in general by lighter material 
in the upper crust. 

ANOMALIES ON INTRUSIVE FORMATIONS. 

The number of stations in intrusive areas is only 7, of which 2 are positive and 5 negative. 
While there are two and one-half times as many negative as positive anomalies, we would not 
be justified in deciding that there is a definite relation between the intrusive formation and 
the gravity anomalies. Many additional stations would have to be established on this for¬ 
mation before any decision can be arrived at in the matter. The mean of the 1916 anomalies 
is slightly smaller than that of the 1912 anomalies and this may be an indication that the new 
depth, 60 km., is nearer the truth than the older depth of 113.7 km. 

ANOMALIES ON EFFUSIVE FORMATIONS. 

On this formation there are eight stations and of the 1912 anomalies 2 are positive and 6 
negative. The mean with regard to sign is —0.005 dyne and without regard to sign it is 0.015 
dyne. The largest anomaly is only 0.028 dyne. Of the 1916 anomalies 5 are positive, 2 negative, 
and 1 zero. The means with and without regard to sign are, respectively, + 0.010 and 0.019 dyne. 

There seems to be no relation between this formation and the anomalies, but the indications 
are very slightly in favor of the greater depth of compensation for the effusive areas. It would 
be of interest and value to have additional stations in areas covered by this formation. 

ANOMALIES ON UNCLASSIFIED FORMATIONS. 

These stations, as the designation implies, could not be associated with any particular 
formations, and it is not possible to draw any conclusions from a study of their relations. 

Of the 26 unclassified stations 18 have positive and only 8 negative 1912 anomalies. This 
is what might be expected for the mean anomaly with regard to sign of all the 219 stations is made 
practically zero (only -0.002 dyne) by the use of the 1912 formula. A greater number of 
stations are in the Paleozoic, Cenozoic, Intrusive, and Effusive formations, which tend to be 
negative, than in the pre-Cambrian and Mesozoic formations, which tend to be positive, there- 


78 


IT. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


fore to have the mean of all stations with regard to sign nearly zero there would be a tendency 
for the unclassified stations to be positive. 

The 1916 anomalies, with depth of 60 km., are practically the same as the 1912 anomalies 
with the depth of 113.7 km. 

An effort was made to learn whether under any one formation the plus anomalies occurred 
more frequently in proportion in one subdivision than in others. No such relationship between 
the sign of the anomaly and the subdivision of a principal geological formation could be found. 
For instance, in the Quaternary division of the Cenozoic there are 11 stations with positive 
and 19 with negative anomalies, or 37 per cent positive. In the whole Cenozoic formation 
there are 22 positive and 32 negative anomalies, the positive anomalies being 41 per cent of 
all. Like results were obtained from other tests. It appears then that the sign of the anomaly 
is in some way connected with a large geologic division as a whole and not with one of its sub¬ 
divisions. 

RELATION BETWEEN THE GRAVITY ANOMALIES AND THE GEOLOGIC FORMATION AT STATIONS 
IN THE UNITED STATES NOT WITHIN 20 MILES OF ANOTHER FORMATION. 

In making the stud} 7 of the relation between the gravity anomalies and the geological 
formation those stations which were not within 20 miles of other formations were separated 
and the data tabulated. These stations and their anomalies are shown in the following tables. 
The results are practically the same as when all stations on a formation are considered. For 
instance, for the Cenozoic stations 65 per cent are negative, while for all stations in that for¬ 
mation 59 per cent are negative. The mean with regard to sign is —0.010 dyne for the Cenozoic 
stations in the table below, while it is —0.007 for all stations in this formation. (See table 
on p. 72.) A similar condition exists for the other formations. The Effusive and Intrusive 
formations have so few stations which are not close to other formations that data for them are 
not given. 

The table given below also contains data for 19 Cenozoic stations not on the coast and not 
within 20 miles of any other formation. If the two Seattle stations are counted as one, the mean 
with regard to sign is —0.009, while without the Seattle value the mean is —0.004. As the 
effect of the coast is not present, these mean values show a decided relation between the anom¬ 
alies and the Cenozoic formation. 

Hayford anomalies for stations in the United States on specified formations and not within 20 miles of other formations. 


Formation and station 

Hayford anomaly 

number 

1912 

1916 

Pre-Cambrian formations: 
57. 

+0.038 

+0.041 

58. 

+ .023 

+ .023 

107. 

+ .024 

+ .026 

185. 

+ .012 

+ .012 

191. 

+ .011 

+ .008 


Formation and station 

Hayford anomaly 

number 

1912 

1916 

Paleozoic formation—Con. 
105. 

-0.021 

-0.017 

106. 

- .013 

- .014 

120. 

- .008 

- .008 

121. 

+ .002 

+ .002 

122. 

+ .011 

+ .012 


Formation and station 

Hayford anomaly 

number 

1912 

1916 

Paleozoic formation—Con. 
176. 

-0.024 

-0.022 

177. 

+ .001 

.000 

178. 

+ .001 

+ .002 

179. 

- .035 

- .027 

181. 

+ .015 

+ .015 


Paleozoic formation: 

12 . 

14. 

20 . 

32 . 

33 . 

34...... 

35 . 

36 . 

37 . 

38 . 

39 . 

59. 

61. 

72. 

74. 


- .027 

- .028 

+ .026 

+ .028 

+ .010 

+ .022 

- .023 

- .020 

- .003 

- .003 

- .019 

- .019 

- .009 

- .010 

- .007 

- .009 

- .005 

- .005 

- .005 

- .007 

- .016 

- .018 

+ .019 

+ .015 

- .029 

- .028 

+ .032 

+ .034 

+ .059 

+ • 057 


123. 

133. 

134. 

135. 

136. 

137. 

138. 

139. 

140. 

141. 

143. 

153. 

155. 

156 

166. 


- .043 

- .030 

- .027 

- .024 

- .012 


.041 

.024 

.027 

.023 

.011 


182. 

184. 

196, 

204. 


- .050 

- .027 
+ .036 

- .026 


- .051 

- .028 
+ .035 
- .025 


+ .001 
- .016 
+ .011 
+ .016 
- .016 

+ .018 

- .023 

- .021 

- .015 

- .023 


+ .002 

- .017 
+ .012 
+ .016 

- .018 

+ .018 
- .020 

- .019 

- .007 

- .021 


207. 

208. 

211 . 


Mesozoic formation: 
40. 

46 . 

47 . 

62. 

70. 


- .029 

- .008 
- .023 


.026 

.008 

.022 


+ .014 
+ .024 
- .021 
+ .031 
- .013 


+ .012 
+ .024 
- .026 
+ .035 
- .001 


88 .. 

89. 

96.. 

101 

104, 


- .010 

- .020 

- .052 
+ .040 

- .024 


- .013 

- .019 

- .051 
+ .045 

- .024 


169. 

170. 

171. 

172. 
174. 


+ .013 
+ .006 

- .030 

- .034 

- .033 


+ .013 
+ .007 
- .026 

- .027 

- .030 


73.. 

76.. 
77. 

94.. 
108. 


+ .005 
+ .002 
+ .029 

- .017 

- .006 


+ .004 
.000 
+ .024 

- .017 

- .008 






























































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


79 


Hay ford anomalies for stations in the United States on specified formations and not within 20 miles of other formations — 

Continued. 


Formation and station 
number 

Hayford anomaly 

Formation and station 
number 

Hayford anomaly 

Formation and station 
number 

Hayford anomaly 

1912 

1916 

1912 

1916 

1912 

1916 

Mesozoic formation—Con. 



Cenozoic formation—Con. 



Cenozoic formation, away 



118. 

+0.014 

+0.009 

97.. 

—0.012 

—0 013 

from coast—Continued. 



186. 

+ .012 

+ .009 

99. 

— .016 

— .013 

93. 

0 044 

0 04? 

187. 

+ .015 

+ .014 

112. 

+ .033 

+ .029 

95.. 

-f 001 

002 

189. 

+ .032 

+ .030 

125. 

- .023 

— .018 

97.. 

— 012 

013 

193. 

+ .030 

+ .028 

126. 

— .022 

- .016 

99 

— .016 

013 

202. 

+ .021 

+ .024 



112 . 

+ .033 

+ 029 



127. 

- .014 

- .007 


Cenozoic formation: 



142. 

+ .011 

+ .009 

142... 

4- .011 

4- 009 

1. 

+ .005 

+ .015 

144. 

— .006 

— .005 

144 

— 006 

— 005 

2. 

+ .018 

+ .027 

145. 

+ .014 

-f .016 

145 

4- 014 

4- 016 

3. 

+ .010 

+ .017 

157. 

- .036 

— .026 

158 . 

— 017 

— 010 

4. 

.000 

+ .004 




160 . 

- .014 

- !oos 

5. 

— .013 

— .010 

158... 

— .017 

.010 





159. 

- .001 

+ .007 

163. 

+ .002 

+ .005 

6. 

+ .016 

+ .017 

160. 

- .014 

- .008 

167.. 

— 012 

— 012 


- .009 

- .008 

161. 

- .021 

— 016 

168 

4- 013 

4- 012 

8. 

+ .027 

+ .030 

163. 

+ .002 

+ .005 

190 . 

4- .017 

4- 015 

9. 

- .020 

- .022 




215.. 

- .029 

- .023 

17. 

— .021 

— .016 

164... 

— .014 

— 010 





167. 

- .012 

- .012 

Effusive and intrusive 



18. 

— .021 

- .008 

168.. 

-f .013 

-f 012 




531 

- .093 

190. 

+ .017 

+ .015 

50. 

- .002 

+ .017 

56/. 


215. 

- .029 

- .023 

51. 

+ .021 

+ .038 

66. 

- .050 

- .049 

217. 

- .010 

— .006 

52 

— .001 

4- 015 

80. 

- .013 

— .010 



111 . 

— 028 

— 019 




Cenozoic formation, away 



113. 

- .027 

- .030 




from coast: 



* 



83. 

- .006 

— .005 

6. 

+ .016 

+ .017 




90. 

- .048 

- .039 

9. 

- .020 

— .022 




92. 

+ .010 

+ .015 

531 






93. 

- .044 

- .042 

56/. 






95. 

+ .001 

- .002 

83. 

- .006 

- .005 





summary. 


Geologic format ion 

Number of stations 

Mean anomaly 

With plus 
anomalies 

With minus 
anomalies 

All 

With regard to sign. 

Without regard to 
sign 

1912 

1916 

1912 

1916 

1912 

1916 

1912 

1916 

Pre-Cambrian. 

5 

5 

0 

0 

5 

+0.022 

+0.022 

0.022 

0. 022 

Palezoic. 

18 

17 

39 

39 

57 

- .009 

- .008 

.020 

.020 

Mesozoic. 

12 

11 

4 

4 

16 

+ .011 

+ .010 

.018 

.017 

Cenozoic.. 

13 

14 

26 

26 

40 

- .010 

- .007 

.019 

.018 

Cenozoic a . 

13 

14 

25 

25 

39 

- .008 

- .005 

.017 

.016 

Cenozoic, away from coast b . 

8 

7 

11 

12 

19 

- .009 

- .OOS 

.020 

.019 

Cenozoic, away from coast a . 

8 

7 

10 

11 

18 

- .004 

- .003 

.016 

.014 

Effusive and intrusive. 

1 

3 

4 

2 

5 

- .007 

+ .004 

.016 

.024 


a With Seattle stations omitted. 


6 With the two Seattle stations counted as one. 














































































































































80 u. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


RELATION BETWEEN THE GRAVITY ANOMALIES AND THE GEOLOGIC FORMATION FOR STATIONS 

IN CANADA. 


There are 42 stations in Canada for which the principal facts are given in the table on page 54. 
The stations with their anomalies (Hayford, 1912) arranged according to the geologic formations 
are given in the following table: 

Canadian stations and Hayford anomalies for specified formations. 


Formation and station 
number 

Hayford 
anomaly 
1912 ' 

Formation and station 
number 

Hayford 
anomaly 
1912 ‘ 

Formation and station 
number 

Pre-Cambrian forma¬ 
tions: 

2. 

-0.010 
- .028 
+ .001 

- .030 

- .002 

- .022 
+ .004 

- .045 
+ .006 
+ .011 

+ .001 

- .043 
4- .002 

Paleozoic formation: 

1. 

-0.018 
- .012 

- .005 
+ .011 
+ .006 

- .021 

- .034 

- .012 
+ .012 

+ .006 
- .006 
- .016 

- .009 

- .011 

Paleozoic formation- 
continued. 

28. 

3. 

4. 

0. 

29. 

5. 


31. 

9. 

8. 

37. 

io.<■».... 

12. 

Mesozoic formation: 

32. 

li. 

10. 

13. 

17. 

33. 

14. 

18. 

34.. 

15. 

19. 

Cenozoic formation: 

35.. 

25. 

20. 

30.. 

21. 

42. 

38. 

22. 


41. 

27. 




Hayford 

anomaly 

1912 

Formation and station 
number 

Hayford 

anomaly 

1912 


Unclassified:. 



23. 

—0.006 

-0.026 

24. 

- .029 

+ .008 

26. 

- .023 

- .009 

36. 

+ .007 

- .011 

39. 

- .009 

+ .007 

- .005 

- .006 

- .004 

- .016 

40. 

- .008 


SUMMARY. 


Geological formation 

Number of stations 

Mean anomaly 

All 

With plus 
anomalies 

With 

minus 

anomalies 

With 
regard to 
sign 

Without 
regard to 
sign 

Pre-Cambrian... 

13 

6 

7 

—0.012 

0 016 

Paleozoic. 

18 

5 

13 

— .008 

OUT 

Mesozoic. 

3 

1 

2 

— .001 

006 

Cenozoic. 

2 

0 

2 

— .010 

010 

Unclassified. 

6 

1 

5 

— .011 

014 

All stations. 

42 

13 

29 

- .009 

.013 


It is a fact worthy of careful consideration that the mean without regard to sign for th^ 
Canadian stations is only 0.013 dyne while for the stations in the United States the mean is 
0.019 dyne. There are only three stations (7 per cent of all) in Canada with anomalies greater 
than 0.030 dyne, while in the United States there are 40 stations (18 per cent of all) with anom¬ 
alies greater than that amount. 

The mean with regard to sign for the Canadian anomalies is —0.009 dyne, while in the 
United States it is —0.002 dyne. The anomalies are computed with the 1912 formula with 
the depth of 113.7 km., so they are comparable with the 1912 anomalies in the United States. 
The writer can see no cause for the mean with regard to sign being so far from that of the 
United States. Nor can he see any reason why the mean without regard to sign for Canadian 
stations is so much smaller than for the stations in the United States. The latter is an indi¬ 
cation that the area covered by the Canadian stations is more nearly in a state of perfect isostasy 
locally. 

The mean with regard to sign for the stations in the pre-Cambrian formation is —0.012, 
which is only 0.003 from the mean of all, and for the Paleozoic and Cenozoic formations the 
means differ only 0.001 dyne from the mean of all. The mean without regard to sign for the three 
Mesozoic stations is —0.001 dyne, which is 0.008 from the mean of all, but this has little signifi¬ 
cance as there are so few stations. 

The conclusion must be drawn that there is no apparent relation between the geologic 
formation and the gravity anomalies at stations in Canada. 































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 81 

RELATION BETWEEN THE GRAVITY ANOMALIES AND THE GEOLOGIC FORMATION FOR STATIONS 

IN INDIA. 

In the table below the stations in India are arranged in groups according to the geologic 
formation. In order to decide on what formations the stations are located, they were plotted 
on a geologic map in the 1890 report of the Geological Survey of India. (See p. 70). 

Indian stations and Hay ford anomalies for specified formations. 


Formation and station number 

Hayford 
anomaly, 
1912 ‘ 

Formation and station number 

Hayford 

anomaly, 

1912 

Pre-Cambrian formations: 

42. 

+0.007 

Cenozoic formation—Continued. 

16.. . 

-0.003 
- .002 
+ .024 

- .005 

- .003 

43. 

+ .023 

22.. 

82. 

+ .008 

26.. . 

84. 

+ .001 

29.. 


30. 

91. 

+ .023 

- .056 
+ .046 

- .039 

32. 

94 

- .078 

95 

35. 

+ .003 

108 

38. 

+ .030 


40. 

— .028 



44. 

— .015 

Paleozoic formation: 

13. 

+ .006 

51 . 

- .027 
+ .031 

- .061 
— .065 

20. 

- .004 

52.. . 

48. 

.000 

58.. . 


60. 

59 

- .011 
— .010 

66. 

+ .033 

88. 

67. 

- .013 

103 

+ .021 


70. 

— .033 

Mesozoic formation: 


71. 

+ .011 


77. 

+ .007 

107. 

+ .022 

78 

- .050 

— .083 

Cenozoic formation: 


83. 

1. 

+ .009 

89. 

4- .019 
— .052 

2. 

— .014 

93. 

3. 

+ .001 

96. 

+ .001 

6. 

- .036 

100... . 

— .066 

15. 

- .022 

101... . 

- .047 




Formation and station number 


Hayford 

anomaly, 

1912 


Effusive formation: 


5. 

8 .. 

14. 

17. 

31. 

45. 


+0.019 
+ .023 
+ .018 
+ .055 
+ .012 
+ .032 


50. 


+ .039 


05.. 

73.. 

97.. 

98.. 
106. 


- .022 

- .027 
+ .003 
+ .029 

- .018 


Unclassified: 


4.. 

9.. 
12 . 
18. 
19. 


- .011 
+ .031 
+ .014 
- .002 
+ .017 


24. 

33. 

37. 

39. 

41 . 


- .013 

- .015 
+ .013 
+ .012 

- .000 


55. 

72. 

75. 

87. 

99. 


- .009 

- .003 
+ .047 
+ .001 
+ .016 


SUMMARY. 


Geological formation 

Number of stations 

Mean anomaly 

All 

With plus 
anomalies 

With 

minus 

anomalies 

With 
regard to 
sign 

Without 
regard to 
sign 

Pre-Cambrian.. 

S 

6 

2 

+0. 002 

0 025 

Paleozoic. 

6 

2 

3 

.000 

. 009 

Mesozoic. 

i 

1 

o 

4- .022 

.022 

Cenozoic.. 

31 

11 

20 

— .017 

. 028 

Effusive. 

12 

9 

3 

4- .014 

. 025 

Unclassified. 

15 

8 

7 

+ .006 

.014 

All stations. 

73 

37 

35 

- .004 

.023 


The anomalies are based upon the United States Coast and Geodetic Survey formula of 
1912, and hence are comparable with the 1912 anomalies in Canada and in the United States. 
The mean with regard to sign is —0.004, and this differs only 0.002 from the mean in the 
United States, which is —0.002 dyne. 

If the latest value of gravity for the base station, Dehra Dun, 979.065 dynes, had been 
used instead of 979.063 dynes, (see p. 55 ), the observed values in India would each be greater 
by 0.002 dyne. Then the mean with regard to sign would be —0.002, the same as for the 
United States. 

There are 8 stations in pre-Cambrian formations in India, of which 6 have positive anomalies 
and 2 negative anomalies. The two stations, Nos. 94 and 108, with negative anomalies, which 
are quite large, and one station, No. 82, with a rather small positive anomaly, are in the extreme 
southern part of the Indian Peninsula on a very extensive area of pre-Cambrian formation. The 
wide extent of this area would probably prevent the existence of large positive anomalies 
(see p. 72) in spite of the density, greater than normal, of the surface and subsurface rocks, but 
there must be in addition some unusual local deficiency in the underlying matter in order to 
59387°—17-6 





































































































































82 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


account for these large negative anomalies. Stations 94 and 108 are only about 8 miles apart 
and should really be considered as only one station, as both must be affected by the same anoma¬ 
lous condition. The mean anomaly at these two stations is —0.048. If these two stations were 
considered as one, then there would be 6 pre-Cambrian stations with positive anomalies and only 
1 with negative anomaly and the mean with regard to sign for this group would be + 0.009, 
which is of the same sign and about one-third the size of the corresponding value for United 
States pre-Cambrian stations. With the exception of the three stations, 82, 94, and 108, noted 
above, all the pre-Cambrian stations are situated on less widely extended areas and have positive 
anomalies, but there is no striking relation between the extent of the area and the magnitude of 
the anomaly except perhaps at station 43, Jubbulpore, which is on a very limited area of the 
formation. The map does not indicate the extent of the formation around station 95, San- 
dakphu. 

There seems to be no relation between the anomaly and the Paleozoic formation, as the 
mean anomaly is nearly normal. This fact should not be given much consideration, as there are 
comparatively few stations in this formation. 

The Mesozoic formation has only one station, and that can not be considered as representing 
any relation whatever. 

The Cenozoic formation has 42 per cent of all the stations and has the only negative mean 
anomaly with regard to sign. This mean anomaly is —0.017. It agrees in sign, but is much 
larger than the Cenozoic mean anomaly with regard to sign in the United States, which is — 0.007 
dyne. All of the Indian Cenozoic stations are back from the coast except one, and it must be 
concluded that there is a very definite relation between the anomalies and the Cenozoic forma¬ 
tion. On page 76 the question was discussed as to whether the Cenozoic formation or the 
proximity to the open coast was the cause of the negative anomalies at coast stations. The 
31 Cenozoic anomalies in India seem to prove that this formation is the main cause of the 
negative anomalies. 

Many of the Cenozoic stations in India are in areas to which great quantities of material 
have been carried from the Himalaya Mountains. It is probable that the larger Cenozoic 
anomalies are above portions of the crust where the recent material is thick and of limited 
horizontal extent. (See discussion under “ pre-Cambrian anomalies,” pp. 72 to 74.) 

It has been held by some geodesists in India® that there is probably a rift in the earth’s 
crust where the large negative anomalies exist. The evidence at hand makes it possible to 
account for the anomalies by the Cenozoic formation in the affected area. 

Of course, it is probable that in India, as in other countries, there are local, and in some 
areas regional, departures from a state of perfect isostasy, but as evidence in the form of gravity 
stations accumulates the theory of isostasy is given added strength. 

The effect of the change of depth from 113.7 km. to 60 km. is discussed at some length on 
pages 97 to 112. It should be noticed that the general effect of the change in the depth is slight, 
though in a few cases it is comparatively large. The anomalies, not being materially changed 
by a decided change in depth, are dependent upon some other condition or conditions in the 
earth’s crust than an erroneous depth. 

The summaries on pages 72 and 81, which give evidence for stations in the United States 
and India, respectively, point strongly to rather definite relations between the sign of the 
anomaly and the surface geology at the station. This relation may be due to variation from 
the normal density for strata in the upper crust, these abnormal densities being compensated 
for by a counterbalancing change in density occurring in the lower crust, possibly to the depth 
of compensation. 

RELATION BETWEEN THE GRAVITY ANOMALIES AND THE GEOLOGIC FORMATION SHOWN 

GRAPHICALLY. 

In figure 17 there are shown areas which have certain geologic formations at the surface 
of the earth. The outlines of the areas were copied from the geologic map of North America 
mentioned on page 70. The scale of this illustration is the same as for those which show the 

a Survey of India, Professional Paper No. 12, On the Origin of the Himalaya Mountains, by Col. S. Q. Burrard, p. 5. 




INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


83 


gravity anomaly contours (figs. 11 to 14). The Cenozoic and Paleozoic areas are shown in 
} 7 ello\v, which is also used on the anomaly maps to show the negative areas. The pre-Cambrian 
and Mesozoic areas are shown in green, the color used to indicate positive areas on the anomaly 
illustrations. 

The largest continuous area is for the Paleozoic formation, and extends from eastern New 
York westward to Minnesota, southwestward to Texas, and southward to Alabama. There is 
practically no portion of this area with any material other than that of the Paleozoic. There 
is a striking similarity between this Paleozoic area and the very extensive negative area which 
extends from New England westward to Iowa and Missouri, as shown in figure 11, which shows 
the Hayford 1912 anomalies. A break in this negative area occurs in Michigan, Ohio, and 
Indiana, where there are four stations with positive anomalies; but their size is small, the 
maximum anomaly being only +0.012 dyne. Within this large Paleozoic area there are 52 
stations with negative anomalies and only 23 with positive anomalies. 

Along the Atlantic coast from New York City southward and along all of the Gulf coast 
the geologic formation is Cenozoic, except for a small break on the coast of South Carolina. 
Figure 17 gives the limits of the coastal areas belonging to this formation (shown in yellow). 
A comparison with figure 11 shows that there is some similarity between the negative areas and 
the Cenozoic areas near the coast. They agree more closely very near the coast. 

There is an extensive area in Minnesota, South Dakota, and North Dakota within which 
the geology is largely pre-Cambrian and Mesozoic. There is a second pre-Cambrian and Meso¬ 
zoic area in Montana and Wyoming. Between these two areas there is an area in which the 
geology is largely Cenozoic. The gravity anomaly map (fig. 11) shows that there are no nega¬ 
tive anomalies within the limits of the above three areas. There are only two stations in the 
intervening Cenozoic area, however. It is worthy of note that there is a narrow extension of 
the first-mentioned pre-Cambrian and Mesozoic area southward into Nebraska and Kansas, and 
that a positive area in figure 11 coincides approximately with this extension. 

A narrow strip of nearly all Cenozoic formation extends southward from South Dakota to 
Texas and New Mexico. A band of negative area in figure 11 partly coincides with this Ceno¬ 
zoic region. If more stations were established within the two areas, they would possibly 
coincide more nearly. 

In western and central Texas there is an area mostly of Mesozoic formation. Figure 11 
shows only three stations within the area, and two are positive. The other station, at Austin, 
is negative, but is very close to the border of the area under consideration. The contours are 
drawn in such a way as to make negative nearly one-half the area. 

A long strip of pre-Cambrian or Mesozoic formation (including a few small areas of other 
formations) extends from the Hudson River southwestward along the Appalachian Mountains 
to Alabama, thence northward in a very narrow band to western Kentucky. There is some 
similarity between this area and the areas of positive anomaly which extend along the Appa¬ 
lachian system from New York to Georgia and Alabama. 

In northern Michigan and Wisconsin and across the international boundary there is an 
area of pre-Cambrian formation in which all of the stations of the United States have positive 
anomalies. 

That portion of the United States which has not been considered above has no extensive 
area in which there is only one geologic formation or combinations of pre-Cambrian and Mesozoic 
or of Paleozoic and Cenozoic. It is interesting to note that in the remainder of the United 
States, not colored in figure 17, the gravity contours show that there are no steep contours 
except in the vicinity of Seattle. The western part of the United States is largely negative, 
but the characteristics of the contours would no doubt be changed greatly by the addition of 
new stations. 

We must conclude that the data contained in figures 11 and 17 substantiate the evidence 
o-iven in the table on pages 71 and 72 that the pre-Cambrian and Mesozoic areas have in general 
positive anomalies and that the Paleozoic and Cenozoic areas have a strong tendency to nega¬ 
tive anomalies. 


84 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

RELATION BETWEEN THE GRAVITY ANOMALIES AND AREAS OF EROSION AND DEPOSITION. 

It has been shown that there is a rather definite relation between the gravity anomalies 
and certain geologic formations and that there is also a relation between the anomalies and 
the topography for coast stations. (See pp. 70 to 83 and also pp. 63 to 69.) It has been indi¬ 
cated that this relation at coast stations is due to the fact that along most of the coast the 
materials, at least at the surface, belong to the Cenozoic geologic formation. (See p. 76.) 

It is probably true that along the whole coast of the United States deposition of the material 
has been taking place in recent geologic time. The natural assumption would be that this 
deposited material is an extra load on the earth’s crust and that in consequence observed gravity 
should be in excess of the computed gravity. This, however, is not the case. An inspection 
of the gravity anomaly map, figure 11, shows that along the coasts observed gravity is, in 
general, less than the computed gravity. 

The logical conclusion from all available data seems to be that isostasy along the coasts 
is nearly perfect on the whole and that the computed gravity is too great because the materials 
in the upper crust are less than normal. According to Barrel! the densities of Cenozoic matter 
vary from 2.40 to 2.50, while on an average the density for the whole land surface of the earth 
is about 2.67, the value used in the computations in this volume. It seems probable that as 
the materials are deposited along the coasts isostatic adjustment takes place and the pressure 
at the depth of compensation is in general normal. In the interior of the country the areas 
covered by the Cenozoic formation, which are likewise areas of recent deposition, are largely 
negative, as shown in figure 11. This is a condition similar to that found along the coasts. 

The areas of recent erosion are greater than those of recent deposition. They are 
areas within which theoretically the gravity anomalies should be negative, but there appears 
to be no such relation. In fact, the oldest formations which no doubt have been subjected to 
the greatest erosion are in general areas of positive anomalies. This is shown by a comparison 
of figures 11 and 17, one of which shows the gravity anomalies and areas of negative and positive 
anomalies and the other limits of large areas of certain geologic formations. The pre-Cambrian 
formation which has been longest exposed to erosion is, in the United States, a formation in 
which the gravity anomalies have a very strong tendency to be positive. 

It is probable that the positive anomalies at stations in the pre-Cambrian formation are 
due largely to the density greater than 2.67 in the material above sea level and also to a density 
greater than normal in the strata in the upper crust below sea level. (See pp. 72 and 81.) No 
assumption need be made in regard to what is the normal density of the materials in a stratum 
at a certain depth below sea level. It is only the deviation from the normal with which we are 
concerned. 

The mountain regions have a number of stations above the general level. They are all 
included in areas which have been and are now subject to erosion. There seems to be no relation 
between the anomalies and the topography in these cases. 

In India there is a broad belt of recent geologic material running approximately east 
and west at the foot of the Himalaya Mountains. The stations on this recent forma¬ 
tion, which no doubt is largely due to the deposition of materials eroded from the moun¬ 
tains, have in general negative anomalies. It is impossible that the addition of materials 
could make the pressure less than normal on the surface at the depth of compensation. We 
may therefore conclude that isostatic adjustment probably follows the deposition of materials 
and that the negative anomaly is probably due to the lighter materials in the upper crust. 
(See p. 82.) 

There seems to be no effect due to the melting of the ice cap on the size and sign of the 
gravity anomaly. This is evidenced by a study of figure 11. If isostasy were perfect at 
the beginning of the ice age and if the isostatic adjustment kept pace with the accumulation 
of ice, thero must have been an adjustment of opposite sign, upon the melting of the ice, for 
on an average the area that was covered by the sheet of ice is very close to a state of equilib¬ 
rium now. 


/ 


Chapter VI.—REGIONAL VERSUS LOCAL DISTRIBUTION OF COMPENSATION. 

On pages 98 to 102 of Special Publication No. 10 there is a discussion of this subject based 
upon data for 41 stations in the United States and 4 stations not in this country. Similar data 
are now available for 124 stations in the United States. 

The question to be considered is whether a topographic feature is compensated for by a 
deficiency of mass directly under it, or whether the topographic feature is compensated for by 
a deficiency of mass distributed through a more extensive portion of the earth’s crust than 
that directly beneath the feature. 

The theory of local compensation postulates that the deficiency of mass under any topo¬ 
graphic feature is uniformly distributed in a column extending directly from the topographic 
feature vertically to a certain depth. In this discussion the depth is taken as 113.7 km. This 
depth is the one used in making the reduction for topography and isostatic compensation. 

The theory of regional compensation postulates, on the other hand, that an individual 
topographic feature is compensated for by a deficiency of mass equal in amount to the topog¬ 
raphy, but of opposite sign, and that this deficiency is uniformly distributed from the surface 
to the depth of compensation, but has a horizontal extent greater than that of the feature 
itself. 

The method of computing the data need not be given here, as the reader can learn of this 
by consulting pages 98 and 99 of Special Publication No. 10. 

The table following gives the data for 124 stations in the United States. In column 
1 are given the number and name of the stations. The effect of topography and compen¬ 
sation computed on the theory of complete local isostasy is given for each station in the 
second column. In columns 3, 5, and 7 are given the effect of local compensation out to the 
outer limits of zones K, M, and O, respectively, while in columns 4, 6, and 8 are given the effect 
of compensation computed upon the theory that the compensation is uniformly distributed 
horizontally to the outer limits of zones K, M, and O, respectively. In column 9 are given 
the Hayford anomalies based on complete local compensation. These are what are called the 
1912 anomalies. (See p. 53.) They are computed by the 1912 Coast and Geodetic Survey 
formula and upon the assumption that the depth of compensation is 113.7 km. In the last 
three columns are given the anomalies for the three methods of regional distribution of com¬ 
pensation with a depth of compensation of 113.7 km. 

Comparison between local and regional isostatic compensation. 


Number and name of station 

Effect of 
topog¬ 
raphy 
and 

compen¬ 

sation 


+0.032 

2. West Palm Beach, Fla... 

3, Pvintft Onrrift, Fla. 

+ .031 
+ .020 


+ .015 


+ .013 

ft. "Ray vllle, La. 

+ .008 

7 Oafv Aston, Tax. 

+ .007 


+ .015 


+ .003 

10. Austin, Tex. (State capi- 
tol).. ... 

- .003 


1 

Effect of compensation within outer limit of 


Hayford 

Anomaly with regional com¬ 
pensation within outer limit 
of— 







anomaly, 




Zone K (18.8 km.) 

Zone M (58.8 km.) 

Zone O (166.7 km.) 

1912 











Zone K 

Zone M 

Zone O 

Local 

Regional 

Local 

Regional 

Local 

Regional 


0.000 

0.000 

+0.001 

+0.003 

+0.010 

+0.021 

+0.008 

+0.008 

+0.006 

-0.003 

.000 

+ .001 

+ .003 

+ .005 

+ .007 

+ .009 

+ .018 

+ .017 

+ .016 

+ .016 

.000 

.000 

.000 

.000 

.000 

.000 

+ .010 

+ .010 

+ .010 

+ .010 

.000 

.000 

.000 

.000 

+ .001 

+ .001 

.000 

.000 

.000 

.000 

.000 

.000 

.000 

.000 

.000 

.000 

- .013 

- .013 

- .013 

- .013 

.000 

- .001 

.000 

- .001 

.000 

- .003 

+ .016 

+ .017 

+ .017 

+ .019 

.000 

.000 

.000 

.000 

.000 

.000 

- .009 

- .009 

- .009 

- .009 

.000 

.000 

.000 

.000 

+ .003 

+ .006 

+ .027 

+ .027 

+ .027 

+ .024 

.000 

- .002 

- .004 

- .007 

- .009 

- .012 

- .020 

- .018 

- .017 

- .017 

- .003 

- .003 

- .009 

- .010 

- .018 

- .019 

- .008 

- .008 

- .007 

- .007 


86 







































86 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 10 


Comparison between local and regional isostatic compensation —Continued. 



Effect of 
topog¬ 
raphy 
and 

compen¬ 

sation 

Effect of compensation within outer limit of— 

Hayford 

Anomaly with regional com¬ 
pensation within outer limit 
of— 

Number and namo of stat ion 

Zone K (18.8 km.) 

Zone M (58.8 km.) 

ZoneX) (166.7 km.) 

anomaly, 

1012 

Zone K 

Zone M 

Zone O 


Local 

Regional 

Local 

Regional 

Local 

Regional 


11. Austin. Tex. (university). 

-0.001 

-0.003 

-0.003 

-0.009 

-0.010 

-0.018 

-0.019 

-0.010 

-0.010 

-0.009 

-0.009 

12. McAlester, Okla. 

4- .001 

- .003 

- .004 

- .010 

- .010 

- .017 

- .017 

- .027 

- .026 

- .027 

- .027 

13. Little Rock, Ark. 

4- .001 

.000 

- . 002 

- .002 

- .005 

- .008 

- .014 

4- .030 

4- .032 

4- .033 

4- .036 

14. Columbia. Tenn. 

4- .006 

- .004 

- .004 

- .009 

- .009 

- .017 

- .017 

+ .026 

4- .026 

4- .026 

4- .026 

15. Atlanta, Ga. 

4- .014 

- .004 

- .005 

- .011 

- .013 

- .021 

- .022 

- .023 

- .022 

- .021 

- .022 

16. McCormick, S. C. 

4- .012 

- .002 

- .002 

- .006 

- .007 

- .012 

- .015 

4- .015 

4- .015 

4- .016 

4- .018 

17. Charleston, S. C. 

4- .016 

.000 

.000 

. 000 

.000 

.000 

4- .001 

- .021 

- .021 

- .021 

- .022 

18. Beaufort, N. C. 

-f .036 

.000 

.000 

.000 

.000 

4- .005 

+ .017 

- .021 

- .021 

- .021 

— .033 

19. Charlottesville, Va. 

4- .002 

- .002 

- .003 

- .010 

- .011 

- .020 

- .024 

- .013 

- .012 

- .012 

- .009 

20. Deer Park, Md. 

+ .041 

- .013 

- .015 

- .029 

- .026 

- .044 

- .035 

4- .010 

4- .012 

4- .007 

4- .001 

21. Washington, D.C. (Coast 
Geodetic SurveyOfiice). 

4- .004 

.000 

- .001 

- . 001 

- .003 

- .005 

- .009 

+ .037 

-t* . 0«jS 

4- .039 

4- .041 

22. Washington, D. C (Smith¬ 
sonian Institution). 

4- .003 

.000 

- .001 

- .001 

- .003 

- .005 

- .009 

4- .039 

4- .040 

4- .041 

4- .043 

23. Baltimore, Md. 

+ .006 

.000 

- .001 

- .001 

- .003 

- .005 

- .009 

- .011 

- .010 

- .009 

— .007 

24. Philadelphia, Pa. 

4- .009 

.000 

- .001 

- .001 

- .002 

- .004 

- .007 

4- .022 

4- .023 

4- .023 

4- .025 

25. Princeton, N. J. 

+ .013 

.000 

- .001 

- .001 

- .003 

- .005 

- .008 

- .019 

- .018 

- .017 

- .016 

26. Hoboken, N. J. 

4- .008 

.000 

.000 

- .001 

- .002 

- .005 

- .009 

+ .024 

4- .024 

-f • 025 

4- .028 

27. New York, N. Y. 

+ .011 

.000 

.000 

- .001 

- .002 

- .006 

- .009 

4- .022 

4- .022 

4- .023 

4- .025 

28. Worcester, Mass. 

29. Boston, Mass. 

+ .018 

- .002 

- .003 

- .007 

- .008 

- .012 

- .011 

- .020 

- .019 

- .019 

— .021 

4- .013 

.000 

. 000 

.000 

- .001 

- .002 

- .005 

4- .005 

-f- . 005 

4- .006 

4- .008 

30. Cambridge, Mass. 

+ .010 

.000 

.000 

- .002 

- .001 

- .005 

- .005 

+ .005 

4- .005 

4- .004 

4- .005 

31. Calais, Me. 

+ .010 

.000 

.000 

- .001 

- .002 

- .003 

- .005 

- .008 

- .008 

- .007 

— . 006 

32. Ithaca, N. Y. 

-f .005 

- .003 

- .005 

- .011 

- .013 

- .023 

- .026 

- .023 

- .021 

- .021 

— .020 

33. Cleveland, Ohio. 

.000 

- .004 

- .004 

- .010 

- .010 

- .019 

- .019 

- .003 

- .003 

- .003 

— .003 

34. Cincinnati, Ohio. 

4- .002 

- .004 

- .004 

- .010 

- .009 

- .020 

- .019 

- .019 

- .019 

- .020 

- .020 

35. Terre Haute. Ind . 

+ .001 

— .002 

- .002 

- .006 

- .007 

— 013 

- .016 

- .014 

- .009 

- .007 

- .009 

- .006 

- .008 

- .005 

36. Chicago, Ill. 

- .002 

- .003 

- .005 

- .007 

- .010 

— .003 

37. Madison, Wis. 

4- . 003 

- .00 4 

- .005 

- .012 

- .013 

- .021 

- .020 

- .005 

- .004 

- .004 

— . 006 

88. St. Louis, Mo. 

+ .001 

- .001 

- .002 

- .005 

- .007 

- .012 

- .014 

- .005 

- .004 

- .003 

— . 003 

39. Kansas City, Mo. 

- .001 

- .004 

- .005 

- .012 

- .013 

- .022 

- .023 

- .016 

- .015 

- .015 

— .015 

40. Ellsworth, Kans. 

- .004 

- .007 

- .008 

- .020 

- .021 

- .038 

- .041 

4- .014 

4- .015 

4- .015 

4- .017 

41. Wallace, Kans. 

.000 

- .018 

- .018 

- .048 

- .048 

- . 0S4 

- . 0S5 

- .012 

- .012 

- .012 

— .011 

42. Colorado Springs. Colo_ 

- .007 

- .036 

- .036 

- .094 

- .093 

- . 165 

- .164 

- .007 

- .007 

- .008 

— .008 

43. Pikes Peak, Colo. 

44. Denver, Colo. 

+ .187 

- .052 

- .044 

- .113 

- . 100 

- .189 

- . 172 

4- .021 

4- .013 

4- .008 

4- .004 

- .015 

- .026 

- .028 

- .076 

- .085 

- . 152 

- . 169 

- .016 

- .014 

- .007 

4- .001 

45. Gunnison, Colo. 

- .001 

- .041 

- .044 

- .120 

- .128 

- .212 

- .210 

4- .020 

4- .023 

4- .028 

4- .018 

46. Grand Junction, Colo. 

- .051 

- .026 

- .028 

- .082 

- .089 

- .156 

- .170 

4- .024 

4- .026 

4- .031 

H- . 038 

47. Green River. Utah. 

48. Pleasant Valley Junction, 

Utah. 

- .043 

- .021 

- .024 

- .067 

- .074 

- .1.30 

- .150 

- .021 

— .018 

- .014 

— . 001 

4- .024 

- .040 

- .041 

- . 103 

- .100 

- . 171 

- . 159 

4- .004 

4- .005 

4- .001 

— .008 

49. Salt Lake City, Utah. 

- .041 

- .026 

- .028 

- .075 

- .078 

- . 137 

- .143 

4- .010 

4- .012 

4- .013 

-f .016 

50. Grand Canvon, Mvo_ 

+ .038 

- .041 

- .042 

- .108 

- .109 

- . 1.80 

- . 165 

- .002 

- .001 

- .001 

- .017 

51. Norris Geyser Basin, Wyo. 

4- .031 

- .040 

- .042 

- .104 

- .105 

- .176 

- .163 

4- .021 

4- .023 

4- .022 

-f- . 008 

52. Lower Geyser Basin, Wyo. 

+ .028 

- .039 

- .041 

- .103 

- .104 

- .177 

- .169 

- .001 

4- .001 

.000 

— . 009 

53. Seattle, Wash. (uni¬ 
versity) . 

- .020 

.000 

.000 

- .002 

- .004 

- .020 

- .038 

- .093 

- .093 

- .091 


54. San Francisco, Cai. 

4- .045 

. 000 

.000 

- .002 

- .003 

4- .009 

4- .033 

- .023 

- .023 

- .022 

— . 047 

55. Mount Hamilton, Cal. 

-1- .120 

- .012 

- .012 

- .017 

- .009 

- .018 

- . 003 

- .003 

- .003 

- .011 

- .018 

56. Seattle, Wash, (high 
school). 

- .018 

.000 

.000 

- .002 

- .004 

- .020 

- . 038 

- .093 

- .09 3 

- .091 

— .075 

57. Iron River, Mich. 

4- .014 

- .007 

- .008 

- .020 

- .020 

- .0.31 

- .024 

4- .038 

4- .039 

4- .038 

4- .031 

58. Ely, Minn. 

4- .008 

- .007 

- .008 

- .019 

- .021 

- .033 

- .029 

4- .023 

4- .024 

4- .025 

4- .019 

59. Pembina, N. Dak. 

- .009 

- .00 4 

- .004 

- . 0T1 

- .012 

- .023 

- .025 

4- .019 

4- .019 

4- .020 

4- .021 

60. Mitchell, S. Dak. 

- .006 

- .007 

- .007 

- .018 

- .019 

- .035 

- .037 

4- .001 

4- .001 

4- .002 

4- .003 

61. Sweetwater. Tex. 

62. Kerrville, Tex. 

63. El Paso, Tex. 

4- .009 

- .011 

- .012 

- .028 

- .029 

- .049 

- .049 

- .029 

- .028 

- .028 

— .029 

+ .013 

- .009 

- .010 

- .024 

- .025 

- .038 

- .032 

4- .031 

4- .032 

4- .032 

4- .025 

+ .001 

- .020 

- .021 

- .054 

- .055 

- .098 

- .104 

4- .007 

4- .008 

4- .008 

4- .013 

64. Nogales, Ariz. 

4- .038 

- .020 

- .020 

- .046 

- .041 

- .076 

- .069 

- .050 

- .050 

- .055 


65. Yuma, Ariz. 

- .010 

- .001 

- .001 

- .004 

- .006 

- .012 

- .018 

4- .009 

4- .009 

4- .011 

4- .015 

66. Compton, Cal. 

.000 

.000 

- .001 

- .003 

- .004 

- .014 

- .024 

- .050 

- .049 

— . 049 

— . 040 

67. Goldfield, Nev. 

4- .027 

- .030 

- .030 

- .074 

- .078 

- .134 

- . 141 

- .013 

- .013 

— .009 

— . 006 

68. Yavapai. Ariz. 

4- .034 

- .030 

- .0.30 

- .080 

- .080 

- . 137 

- .129 

4- .001 

4- .001 

H- .001 

— mr 

69. Grand Canyon, Ariz. 

- .096 

- .028 

- .029 

- .079 

- .080 

- .136 

- .127 

- .010 

- .009 

— .009 

— 019 

70. Gallup, N. Mex. 

+ .014 

- .036 

- .036 

- .095 

- .095 

- .163 

- .156 

- .013 

- .013 

- .013 

- .020 

71. Las Vegas, N. Mex. 

4- .017 

- .036 

- .035 

- .094 

- .094 

- .160 

- .150 

4- . 003 

4- .002 

4- .003 

— 007 

72. Shamrock, Tex. 

+ .007 

- .013 

- .012 

- .031 

- .031 

— . 055 

- .056 

4- .032 

4- .031 

4- .032 

4- . 033 

73. Denison, Tex. 

- .001 

- .004 

- .004 

- .010 

- .009 

- .018 

- .017 

4- .005 

4- .005 

4- .004 

4- 004 

74. Minneapolis, Minn. 

- .005 

- .004 

- .005 

- .012 

- .013 

- .022 

- .024 

4- .059 

4- .060 

4- .060 

4- .061 

75. Lead, £f. Dak. 

+ .044 

- .026 

- .027 

- .064 

- .061 

- . 102 

- .089 

4- .052 

4- .053 

4- .049 

4- .039 

76. Bismarck, N. Dak. 

- .005 

- .008 

- . 009 

- .024 

- .026 

- .044 

- .047 

4- .002 

4- .003 

-f . 004 

4- .005 
4- 038 

77. Hinsdale, Mont. 

- .017 

- .010 

- .012 

- .030 

- .034 

- .058 

- .067 

4- .029 

4- .031 

+ .033 

78. Sandpoint, Idaho. 

79. Boise, Idano. 

- .044 

- .014 

- .014 

- .045 

- .049 

- .086 

- .095 

4- .002 

4- .002 

4- .006 

4- .011 

- .042 

- .016 

- .018 

- .047 

- .051 

- .094 

- . 108 

4- .008 

4- .010 

4- .612 

4- .022 

80. Astoria, Oreg. 

+ .008 

.000 

.000 

- .002 

- .005 

.000 

4- .008 

- .013 

- .013 

- .010 

- .021 























































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


87 


Comparison between local and regional isostatic compensation —Continued. 


Number and name of stat ion 

Effect of 
topog¬ 
raphy 
and 

compen¬ 

sation 

_ 

E 

fleet of compensation within outer limit of— 

Hayford 

anomaly, 

1912 

Anomaly with regional com¬ 
pensation within outer limit 
of— 

Zone K (18.8 km.) 

Zone M (58.8 km.) 

Zone O (166.7 km.) 

Zone K 

Zone M 

Zone O 

Local 

Regional 

Local 

Regional 

Local 

Regional 

81. Sisson, Cal. 

+0.015 

-0.022 

-0.026 

-0.058 

-0.059 

-0.096 

-0.088 

-0.010 

-0.006 

-0.009 

-0.018 

82. Rock Springs, Wyo... 

- .001 

- .036 

- .034 

- .093 

- .093 

- .169 

- .177 

+ .013 

+ .011 

+ .013 

+ .021 

83. Paxton, Nebr. 

+ .002 

- .014 

- .016 

- .041 

- .043 

- .073 

- .077 

- .006 

- .004 

- .004 

— .002 

84. Washington, D. C. (Bu- 












reau of Standards'). 

+ .012 

.000 

- .001 

- .001 

- .003 

- .005 

- .009 

+ .037 

+ .038 

+ . 039 

+ .041 

85. North Hero, Vt.. 

- .009 

.000 

- .001 

- .003 

- .007 

- .012 

- .016 

+ .001 

+ .002 

+ .005 

+ .005 

86. Lake Placid, N. Y. 

+ .032 

— .011 

— .012 

— .024 

— . 021 

033 

non 





87. Potsdam, N. Y. 

- .004 

- .002 

- .003 

- .008 

- .010 

- !oi7 

- .017 

+ .021 

+ .022 

+ .023 

+ .021 

88. Wilson, N. Y. 

- .002 

. 000 

- .002 

- .003 

- .004 

- .011 

- .017 

- .010 

- .008 

— .009 

— .004 

89. Alpena, Mich. 

.000 

- .004 

- .003 

- .010 

- .OOS 

- .016 

- .016 

— .020 

- .021 

- .022 

- .020 

90. Virginia Beach, Va. 

+ .025 

.000 

.000 

.000 

.000 

.000 

+ .002 

- .048 

- .048 

- .048 

- .050 

91. Durham, N. C. 

+ .014 

.000 

- .002 

- .004 

- .006 

- .008 

- .010 

+ .036 

+ .038 

+ .038 

+ .038 

92. Femandina, Fla. 

+ .017 

.000 

.000 

.000 

.000 

.000 

+ .001 

+ .010 

+ .010 

+ .010 

+ .009 

93. Wilmer, Ala. 

+ .018 

.00-0 

- .001 

- .001 

- .002 

- .001 

- .002 

- .044 

- .043 

- .043 

- .043 

94. Aliceville, Ala. 

+ .008 

.000 

- .001 

- .001 

- .013 

- .005 

- .007 

- .017 

- . 016 

- .015 

- .015 

95. New Madrid, Mo. 

+ .001 

.000 

- .002 

- .1/01 

- .004 

- .007 

- .011 

+ .001 

+ .003 

+ .004 

+ .005 

96. Mena, Ark. 

+ .015 

- .004 

- .006 

- .012 

- .013 

- .020 

- .017 

- .052 

- .050 

- .051 

- .055 

97. Nacogdoches, Tex. 

+ .008 

.000 

- .002 

- .001 

- .004 

- .005 

- .006 

- .012 

- .010 

- .009 

- .011 

98. Alpine, Tex. 

+ .033 

- .022 

- .025 

- .061 

- .063 

- .098 

- . 0S5 

+ .021 

+ .024 

+ .023 

+ .008 

99. Farwell, Tex. 

+ .011 

- .020 

- .021 

- .055 

- .056 

- .096 

- .094 

- .016 

- .015 

- .015 

- .018 

100. Guymon, Okla. 

- .001 

- .014 

- .016 

- .042 

- .046 

- .077 

- .081 

- .017 

- .015 

- .013 

- .013 

101. Helenwood, Tenn. 

+ .015 

- .007 

- .008 

- .020 

- .020 

- .033 

- .030 

+ .040 

+ .041 

+ .040 

+ .037 

102. Cloudland, Tenn. 

+ .130 

- .019 

- .017 

- .039 

- .033 

- .058 

- .043 

+ .004 

+ .002 

- .002 

- .011 

103. Hughes, Tenn. 

+ .053 

- .018 

- .018 

- .038 

- .034 

- .057 

- .044 

- .029 

- .029 

- .033 

- .042 

104. Charleston, W. Va. 

- .010 

- . c04 

- .005 

- .012 

- .015 

- .027 

- .035 

- .024 

- .023 

- .021 

- .016 

105. State College, Pa. 

+ .010 

- .005 

- .007 

- .016 

- .018 

- .030 

- .030 

- .021 

- . jl9 

- .019 

- .021 

106. Fort Kent, Me. 

+ .001 

- .002 

- .003 

- .006 

- .009 

- .016 

- .017 

- .013 

- .012 

- .010 

- .012 

107. Prentice, Wis. 

+ .010 

- .007 

- .008 

- .019 

- .019 

- .032 

- .028 

+ .024 

+ .025 

+ .024 

+ .020 

108. Fergus Falls, Minn. 

+ .001 

- .005 

- .006 

- .014 

- .015 

- .026 

- .029 

- .006 

- .005 

- .005 

- .003 

109. Sheridan, W T yo. 

- .031 

- .020 

- .021 

- .068 

- .077 

- .120 

- .118 

+ .032 

+ .033 

+ .041 

+ .030 

110. Boulder, Mont. 

- .007 

- .031 

- .032 

- .077 

- .074 

- .137 

- .139 

- .015 

- .014 

- .018 

- .013 

111. Skykomish, Wash. 

- .047 

- .014 

- .018 

- .038 

- .038 

- .058 

- .047 

- .028 

- .024 

- .028 

- .039 

112. Olympia, Wash. 

- .012 

.000 

.000 

- .002 

- .003 

- .014 

- .025 

+ .033 

+ .033 

+ .034 

+ .044 

113. Heppher, Oreg. 

- .007 

- .010 

- .010 

- .027 

- .029 

- .056 

- .067 

- .027 

- .027 

- .025 

- .016 

114. Tnic’kee, Cal. 

+ .057 

- .035 

- .035 

- .085 

- .081 

- .129 

- .100 

- .028 

- .028 

- .032 

- .057 

115. Wmnemucca, Nev. 

- .004 

- .022 

- .023 

- .062 

- .065 

- .116 

- .128 

- .009 

- .008 

- .006 

+ .003 

116. Elv, Nev. 

+ .020 

- .038 

- .039 

- .094 

- .093 

- .159 

- . 150 

- .021 

- .020 

- .022 

- .030 

117. Guernsey, Wyo. 

- .016 

- .022 

- .024 

- .062 

- .067 

- .117 

- .127 

+ .036 

+ . 03S 

+ .041 

+ .046 

118. Pierre, S'. Dak. 

- .013 

- .007 

- .008 

- .021 

- .023 

- .042 

- .048 

+ .014 

+ .015 

+ .016 

+ .020 

119. Fort Dodge, Iowa. 

+ .002 

- .004 

- .006 

- .014 

- .015 

- .026 

- .027 

+ .015 

+ .017 

+ .016 

+ .016 

120. Keithsburg, Ill. 

- .003 

- .004 

- .003 

- .009 

- .008 

- .016 

- .016 

- .008 

- .009 

- .009 

- .008 

121. Grand Rapids, Mich. 

+ .003 

- .004 

- .004 

- .010 

- .009 

- .018 

- .017 

+ .002 

+ .002 

+ .001 

+ .001 

122. Angola, Ind. 

+ .011 

- .004 

- .005 

- .011 

- .012 

- .019 

- .01S 

"h .011 

+ .012 

+ .012 

+ .010 

123. Albanv, N. Y. 

- .006 

- .001 

- .002 

- .008 

- .011 

- .020 

- .025 

- .043 

- .042 

- .040 

- .038 

1 4. Port Jervis, N. Y. 

+ .003 

- .003 

- .004 

- .011 

- .013 

- .020 

- .019 

- .033 

- .032 

- .031 

- .034 

Mean with regard to 












sign. 








— .002 

- .001 

- .001 

- .002 

Mean without regard to 









sign. 








.020 

.019 

.020 

.020 

Mean with regard to 









sign *. 








.000 

+ .001 

+ .001 

- .001 

Mean without regard to 












sign a. 








.018 

.018 

.018 

.019 














a Omitting Seattle stations. 


If we ignore the two Seattle stations, which seems to he justifiable on account of their 
excessively large anomalies (see p. 53), we have means with regard to sign, which are zero or 
0.001 dyne, for the four methods of horizontal distribution of the compensation. Also three 
of the methods have means without regard to sign of 0.018 dyne and one of them a mean 
of 0.019 dyne. These anomalies show that for the country taken as a whole, no one of the 
methods has an advantage over the others. 

It can be readily understood that for a station on a plateau of considerable horizontal 
extent the effect of compensation should be the same by the several methods, for the amount 
of compensation under any portion of the area near the station would be the same for each. 
If the country has varied topography, then the effect of compensation will be different for the 
different methods of distribution. For instance, in a valley with mountains on cither side the 































































































88 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


effect of the compensation will be different if some of the compensation of the mountain masses 
is extended horizontally under the valley. 

The decision as to whether we have local or regional compensation must depend upon 
whether any one method has a general application to a set of stations which exist under the 
same or similar conditions. For instance, if mountain stations have smaller anomalies on an 
average, and if the mean of all these stations with regard to sign should be close to zero when 
reduced by a given method, then we should be justified in concluding that this method is based 
upon more nearly correct assumptions than a method which gives larger anomalies and a larger 
mean with regard to sign. 

In order to make the regional method of reduction logical, the compensation of each topo¬ 
graphic feature should be computed separately to the limits of the zone having the topographic 
feature at its center. The method of computation actually adopted may give very erroneous 
results. For instance, let us assume that the compensation is distributed regionally within 
zone O, with the station at its center. It may happen that the station is in a broad valley 
or on a plain with mountains surrounding it at a distance of about 167 kms. None of the 
compensation under the mountains would be taken into account in making the reductions, 
and the computed value of gravity would be too great. On the other hand, if the station were 
in the mountains, with valleys or plains just beyond the limits of zone O, then none of the 
compensation of the mountains would be distributed to the valleys or plains, and the computed 
value of gravity at the station would be too small. Therefore, in making the reductions by 
the regional method the compensation for each topographic feature should be distributed 
separately before making the computations to obtain its effect. This, of course, would be 
possible, but it would be such a laborious process that it would not be practicable. 

RELATION OF LOCAL-COMPENSATION ANOMALIES AND REGIONAL-COMPENSATION ANOMALIES 

TO THE TOPOGRAPHY. 


The tables given in the following pages contain the anomalies computed by the local and 
the three regional methods, with the stations arranged according to the same topographic 
groupings as are shown on pages 63 to 67. 

Local and regional anomalies at 18 coast stations arranged in the order of their distances from the 1000-fathom line. 


Hay ford 
anomaly 


Number and name of station. 


1912 

(local 


compen¬ 

sation) 


54. San Francisco, Cal.I —0.023 

18. Beaufort, N. C.; —.021 

80. Astoria, Oreg. — .013 

90. Virginia Beach, Va.: — .048 

92. Fernandina, Fla. +.010 

1. Key West, Fla. + .008 

s. Point Isabel, Tex. + .027 

5. New Orleans, La.! — .013 

4. Apalachicola, Fla. .000 

27. New York, N. Y. + . 022 


Anomaly with regional com¬ 
pensation within outer 
limit of— 

Number and name of station 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Zone K 

'Zone M 

Zone O 

Zone K 

Zone M 

Zone O 

-0.023 

-0.022 

-0.047 

26. Hoboken, N. J. 

+0.024 

+0.024 

+0.025 

+0.028 

- .021 

- .021 

- .033 

66. Compton, Cal. 

- .050 

- .049 

- .048 

- .037 

- .013 

- .010 

- .021 

2. West Palm Beach, Fla. 

+ .018 

+ .017 

+ .016 

+ .016 

- .048 

- .048 

- .050 

3. Punta Gorda, Fla. 

+ .010 

+ .010 

+ .010 

+ .010 

+ .010 

+ .010 

+ .009 

29. Boston, Mass. 

+ .005 

+ .005 

+ .006 

+ .008 

+ .008 

+ .006 

- .003 

30. Cambridge, Mass. 

+ .005 

+ .005 

+ .006 

+ .007 

+ .027 

+ .027 

+ .024 

17. Charleston, S. C. 

- .021 

- .021 

- .021 

- .022 

- .013 

- .013 

- .013 

7. Galveston, Tex. 

- .009 

- .009 

- .009 

- .009 

. 000 

. 000 

.ooo 






+ .022 

+ .023 

+ .025 

Mean with regard to sign. 

- .004 

- .004 

- .004 

- .008 




Mean without regard to 








sign. 

.018 

.018 

.018 

.020 


For coast stations the mean anomalies with and without regard to sign are the same for 
local and for regional compensation through zones K and M. In no case does a regional anomaly 
with compensation out through zones K and M differ more than 0.003 dyne from a local com¬ 
pensation anomaly. This is as one might expect, for the topography is low and the water 
within zone M is comparatively shallow, so the distribution of compensation regionally can have 
little influence on the value of the effect of the compensation. 

The anomalies for regional compensation to the outer limit of zone O have decidedly larger 
negative values than those for local compensation at San Francisco (No. 54), at Beaufort (No. 18), 

























































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


89 


and at Astoria (No. 80), while at Key West (No. 1) the anomaly changes from +0.008 to - 0.003. 
These decided differences are to be expected for a portion of the compensation under the water, 
v hicli is of positive sign, is distributed through the zone, and as the vertical component of its 
attraction is greater for the regional distribution than for the local it increases the computed 
value of gravity at the station and hence makes the anomaly g—g c have a smaller positive or a 
larger negative value. 

The anomaly at Compton (No. 66) is changed in the opposite direction. This is due to 
the distribution of the compensation for the high land, which decreases the computed value 
of the intensity of gravity at the station. 

The mean anomaly with regard to sign for regional compensation to the outer limit of 
zone O is -0.006, while the mean for local compensation is -0.004. The means without 
regard to sign for these anomalies are, respectively, 0.020 and 0.018. The differences are small 
but they do not favor distribution of compensation regionally to the outer limit of zone O. 

The reason why the mean with regard to sign is negative for the Hayford anomalies at 
coast stations is discussed under the heading "Relation between the gravity anomalies and the 
geologic formation.” (See p. 70.) 

The following table gives the local and regional anomalies at stations near the coast, the 
stations being arranged in the order of their distance from the open coast. These distances 
are given in the table on page 64. 


Local and regional anomalies at 25 stations near the coast, arranged in the order of their distances from the open coast. 


N umber and name of station 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Number and name of station 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Zone K 

Zone M 

Zone O 

Zone K 

Zone M 

Zone O 

31. Calais, Me. 

-0.008 

-0.008 

-0.007 

-0.006 

123. Albany, N. Y. 

-0.043 

-0.042 

- 0.010 

-0.038 

25. Princeton, N. J. 

- .019 

- .018 

- .017 

- .016 

16. McCormick, S. C. 

+ .015 

+ .015 

+ .016 

+ .018 

03. Wilmer, Ala. 

- .014 

- .043 

- .043 

- .043 

10. Austin, Tex. (Capitol)_ 

- .008 

- .008 

- .007 

- .007 

23. Baltimore, Md. 

- .011 

- .010 

- .009 

- .007 

11. Austin, Tex. (University). 

- .010 

- .010 

- .009 

- .009 

28. Worcester, Mass. 

- .020 

- .019 

- .019 

- .021 

19. Charlottesville, Va... 

— .013 

— 012 

— 012 

OOQ 

24. Philadelphia, Pa. 

+ .022 

+ .023 

4- .023 

+ .025 

32. Ithaca, N. Y. 

— .023 

— 021 

— 021 

— 020 

124. Port Jervis, N. Y. 

- .033 

- .032 

- .031 

— .034 

94. Alicoville, Ala... . 

— 017 

01 f> 

015 

01-5 

81. Sisson, Cal.. 

- .010 

- .006 

- .009 

- .018 

62. Kerrville, Tex. 

+ 0.31 

-f !032 

-f 032 

4 - 025 

21. Washington, D. C. (Coast 





106. Fort Kent Me. 

- .013 

- 1012 

- !oio 

- ! 012 

& Geodetic Survey Of- 





6 . Ravville, La. 

+ .016 

+ .017 

+ .017 

+ .019 


+ .037 

+ .038 

+ .039 

+ .041 






22. Washington, D. C. (Smith- 

Mean with regard to sign. 

- .002 

- .001 

- .001 

- .001 

sonian Institution). 

+ .039 

+ .040 

+ .041 

+ .043 

Mean without regard to 










sign. 

.022 

.021 

.021 

.022 

84. Washington, D. C. (Bu- 










reau of Standards). 

+ .037 

+ .038 

+ .039 

+ .041 






91. Durham, N. C. 

4- .036 

+ . 038 

+ .038 

+ .038 






9. Laredo, Tex. 

- .020 

- .020 

- .019 

- .020 






65. Yuma, Ariz. 

+ .009 

+ .009 

+ .011 

+ .015 






97. Nacogdoches, Tex. 

- .011 

- .009 

- .008 

- .010 







There are only three stations at which there are decided differences between the local and 
regional anomalies in the above table. These are Sisson (No. 81), where the change is 0.008, 
Yuma (No. 65), where it is 0.006, and Kerrville (No. 62), where the change is also 0.006. 

As practically all of the 25 stations under consideration are in topography with little relief, 
one would expect the anomalies to be little changed by the different methods of making the 
reductions. The mean anomalies with and without regard to sign have a total range of only 
0.001. These stations, therefore, give no information as to whether one of the methods has any 
advantage over any other one. 

The following table gives the local and regional anomalies at 39 stations in the interior 
which are not in mountainous regions. The stations are arranged in the order of their elevation 
above sea level. These elevations are given in the table on page 64. 
























































90 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Local and regional anomalies at 39 stations in the interior, and not in mountainous regions, arranged in the order of elevation. 


Number and name of station 


Hayford 

anomaly, 


1912 


(local 


compen- 


95. 

88 . 

13. 

87. 

35. 


sation) 


New Madrid, Mo. 
Wilson, N. Y.... 
Little Rock, Ark. 
Potsdam, N. Y.. 
Terre Haute, Lid 


+0.001 
- .010 
+ .030 
+ .021 
- .009 


38. St. Louis, Mo. 

120. Keithsburf, Ill- 

89. Alpena, Mich. 

36. Chicago, Ill. 

104. Charleston, W. Va 


.005 

.008 

.020 

.007 

.024 


14. Columbia, Tenu- 

33. Cleveland, Ohio. 

73. Denison, Tex. 

121. Grand Rapids, Mich 
12. McAlester, Okla- 


+ .026 

- .003 
4- .005 
+ .002 

- .027 


59. 

34. 

74. 

37. 

39. 


Pembina, N. Tak.. 
Cincinnati, Ohio... 
Minneapolis. Minn. 

Madison, Wis. 

Kansas City, Mo... 


+ .019 

- .019 
+ .059 

- .005 

- .016 




Anomaly with regional com¬ 
pensation within outer 
limit of— 

1 

Number and name of station. 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Zone K 

Zone M 

Zone O 

Zone K 

Zone M 

Zone O 

+0.003 

+0.004 

+0.005 

122. Angola, Ind. 

+0. 011 

+0.012 

+0.012 

+0.010 

- .008 

- .009 

- .004 

15. Atlanta, Ga. 

- .023 

- .022 

- .021 

- .022 

+ .032 

+ .033 

+ .036 

119. Fort 1 odge, Iowa. 

+ .015 

+ .017 

+ .016 

+ .016 

+ .022 

+ .023 

+ .021 

108. Fergus Falls, Minn. 

- .006 

- .005 

- .005 

- .003 

- .009 

- .008 

- .006 

96. Mena, Ark. 

- .052 

- .050 

- .051 

— .055 

- .004 

- .003 

- .003 

60. Mitchell, S. Dak. 

+ .001 

+ .002 

+ .004 

+ .005 

— .007 

— .007 

— .006 

58. Ely, Minn. 

+ .023 

-f .025 

-f .026 

+ 021 

- .021 

- .022 

- .020 

118. Pierre, S. Dak. 

+ .014 

+ .015 

+ .016 

+ .020 

- .008 

- .008 

- .006 

57. Iron River, Mich. 

+ .038 

+ .039 

+ .038 

+ .031 

- .023 

- .021 

- .016 

40. Ellsworth, Kans. 

+ .011 

+ .015 

+ .015 

+ .017 

+ .026 

+ .026 

+ .026 

107. Prentiss, Wis. 

+ .024 

+ .025 

+ .024 

+ .020 

- .003 

- .003 

- .003 

76. Bismarck, N. Dak. 

+ .002 

+ .003 

+ .004 

+ .005 

+ .005 

+ .004 

+ .004 

61. Sweetwater, Tex. 

- .029 

- .028 

- .028 

- .029 

+ .003 

+ .003 

+ .003 

77. Hinsdale, Mont. 

+ .029 

+ .031 

+ .033 

+ .038 

- .026 

- .027 

- .027 

72. Shamrock, Tex. 

+ .032 

+ .031 

+ .032 

+ .033 

+ .019 

+ .020 

+ .021 

83. Paxton, Nebr. 

- ,006 

- .004 

- .004 

- .002 

- .019 

- .020 

- .020 

100. Guymon, Okla. 

- .017 

- .015 

- .013 

- .013 

+ .060 

+ .060 

+ .061 

41. Wallace, Kans. 

- .012 

- .012 

- .012 

- .011 

- .004 

- .004 

- .006 

99. Farwell,Tex. 

- .016 

- .015 

- .015 

- .018 

- .015 

- .015 

- .015 









Mean with regard to sign. 

+ .001 

+ .002 

+ .002 

+ .003 




Mean without regard to 








sign. 

.017 

.018 

.018 

.017 


The differences between the anomalies for the locai and for the regional compensation to 
the outer limits of zones K and M are very small, there being only two as great as 0.004 and 
only five others as great as 0.003. 

The differences between the anomalies for local compensation and for regional compensation 
to the outer limit of zone O are onfy slightly larger, the maximum difference being 0.009. 

As with the stations back from the coast, the differences between the local and regional 
anomalies may be expected to be small, for the topography in the vicinity of these stations is 
fairly level. 

The means without regard to sign for the different methods are practically the same, while 
the means with regard to sign differ only slightly. It must be considered that there is no evi¬ 
dence here in favor of either method, although the slight differences in the means with regard to 
sign favor the local distribution. 

There are 22 stations in the United States in mountainous regions and below the general 
level, the anomalies for which by' the local and regional methods of distribution of compensa¬ 
tion are given in the following table. The elevations of the stations and the distances of the 
stations below the general elevation are given in the table on page 66. 

Local and regional anomalies at 22 stations in mountainous regions and below the general level, arranged in the order of their 

distances below the general level. 


Number and name of station 


70. Gallup, N. Mex. 

105. State College, Pa. 

67. Goldfield, Nev. 

85. North Hero, Vt.„- 

63. El Paso, Tex. 

113. Beppner, Oreg. 

112. Olympia, Wash. 

110. Boulder, Mont. 

111. Skykomish, Wash. 

117. Guernsey, Wyo. 

115. Wlnnenmucca, Nev. 

109. Sheridan, Wyo. 

82. Rock Springs. tVyo. 

45. Gunnison, Colo. 

42. Colorado Springs, Colo_ 


Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Number and name of station 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Zone K 

Zone M 

Zone O 

Zone K 

Zone M 

Zone O 

-0.013 

-0.013 

-0.013 

-0.020 

49. Salt Lake City, Utah. 

+0.010 

+0.012 

+0.013 

+0.016 

- .021 

- .019 

- .019 

- .021 

44. Denver, Colo. 

- .016 

- .014 

- .007 

+ .001 

- .013 

- .013 

- .012 

- .009 

79. Boise, Idaho. 

+ .008 

+ .010 

+ .012 

+ .022 

+ .001 

+ .002 

+ .005 

+ .005 

78. Sand point, Idaho. 

+ .002 

+ .002 

+ .006 

+ .011 

+ .007 

+ .008 

+ .008 

+ .013 

69. Grand Canyon, Ariz. 

- .010 

- .009 

- .009 

- .019 

- .027 

- .027 

- .025 

- .016 

46. Grand Junction, Colo. 

+ .024 

+ .026 

+ .031 

+ .038 

+ .033 

+ .033 

+ .034 

+ .044 

47. Green River, Utah. 

- .021 

- .018 

- .014 

- .001 

— .015 

— .014 

— .018 

— .013 






- .028 

- .024 

- .028 

- .039 

Mean with regard to 





+ .036 

+ .038 

+ .041 

+ .046 

sign. 

.000 

+ .001 

+ .003 

+ .006 





Mean without regard to 


- .009 

- .008 

- .006 

+ .003 

sign. 

.017 

.017 

.018 

.019 

+ .032 

+ .033 

+ .041 

+ .030 






+ .013 

+ .011 

+ .013 

+ .021 






+ .020 

+ .023 

+ .028 

+ .018 






- .007 

- .007 

- .008 

- .008 









































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


91 


The anomalies for the regional compensation to the outer limits of zones K and M are only 
slightly different from the anomalies for local compensation and the means with regard to sign show 
only a slight advantage for the local compensation method. The means without regard to sign 
for the three sets of anomalies are practically the same. But for regional compensation to the 
outer limit of zone O, there are four anomalies which are larger than the maximum anomaly for 
local compensation, 0.036. While the average anomaly without regard to sign is nearly the same 
for the two methods, the mean with regard to sign is zero for local compensation and +0.006 for 
regional compensation to the outer limit of zone O. This, it is believed, is comparatively strong 
evidence in favor of local distribution of compensation. This is especially true as the mean with 
regard to sign for 122 stations, regional compensation considered to the outer limit of zone O 
(see bottom of table on p. 87), is —0.001. The mean in the above table is, therefore, 0.007 dif¬ 
ferent from the mean of all. 

As the compensation of the higher land is brought closer to the station it is natural that 
the computed gravity at the stations should be less than for the local distribution of the 
compensation. 

The last table of this series gives the local and regional anomalies at 18 stations in moun¬ 
tainous regions which are above the general level. The elevations of the stations above sea 
level and the distances above the general level are given in the table on page 66. 


Local and regional anomalies at 18 stations in mountainous regions and above the general level , arranged in the order of their 

distances above the general level. 


Number and name of station 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer j 
limit of— 

Number and name of station 

Hayford 

anomaly, 

1912 

(local 

compen¬ 

sation) 

Anomaly with regional com¬ 
pensation within outer 
limit of— 

Zone K 

Zone M 

Zone O 

Zone K 

Zone M 

Zone O 


+0.003 

+0.002 

+ 0.003 

-0.007 

86. Lake Placid, N. Y. 

+0.006 

+0.007 

+0.003 

—0. 007 


- .021 

- .020 

- .022 

- .030 

103. Hughes, Terin. 

- .029 

- .029 

— .033 

— .042 


+ .040 

+ .041 

+ .040 

+ .037 

75. Lead, S. Dak. 

+ .052 

+ .053 

+ .049 

+ .039 

52. Lower Geyser Basin, Wyo. 

- .001 

+ .001 

.000 

- .009 

68. Yavapai, Ariz. 

+ .001 

+ .001 

+ .001 

- .007 

51. Norris Geyser Basin, Wyo. 

+ .021 

+ .023 

+ .022 

+ .008 

114. Truekee,Cal. 

- .028 

- .028 

- .032 

- .057 

48. Pleasant Valley Junction, 





55. Mount Hamilton, Cal. 

- .003 

- .003 

- .011 

- .018 

Utah. 

+ .004 

+ .005 

+ .001 

- .008 

102. Cloudiand, Tenn. 

+ .004 

+ .002 

- .002 

- .011 


- .002 

- .001 

- .001 

- .017 

43. Pikes Peak, Colo. 

+ .021 

+ .013 

+ .008 

-f .001 


+ 021 

4- 024 

+ 023 

-f. 008 






64. Nogales, Ariz. 

- .050 

- !o50 

— .055 

- ! 057 

Mean with regard to sign. 

+ .003 

+ .003 

.000 

- .010 

20. Deer Park, Md. 

+ .010 

+ .012 

+ .007 

+ .001 

Mean without regard to 










sign. 

1 

.018 

.018 

.017 

.020 


This table gives strong evidence that the local compensation and the regional compensation 
to the outer limits of zones K and M are much nearer the truth than regional compensation to 
the outer limit of zone O. There is some slight evidence in favor of regional compensation 
to the outer limit of zone M. 

The mean anomaly without regard to sign for regional compensation to the outer limit of 
zone O is only 0.002 larger than for the local method, but the mean with regard to sign is 
— 0.010 while for the local method it is only +0.003, and the former is 0.009 different from 
the mean for 122 stations, —0.001 (see p. 87). 

The progressive decrease algebraically in the regional anomalies as the radius of distribution 
of the compensation is increased is what one would naturally expect, for as the compensation 
is placed farther and farther from the station it has less effect, and so the computed gravity is 
increased and the anomalies are decreased algebraically. 

CONCLUSION. 

The evidence and analysis given on pages 85 to 91 lead to the definite conclusion that the 
local distribution of compensation is much nearer the truth than the regional distribution of 
the compensation to a distance of 166.7 km. from the stations. This conclusion is based upon 
the great difference of 0.016 dyne between the mean zone-0 anomaly for stations in moun- 























































92 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


tainous regions below the general level and the mean zone-0 anomaly at stations in moun¬ 
tainous regions above the general level. The difference between the mean anomalies for the 
local method for these two groups of stations is only 0.003. 

There is no evidence which favors the local as against the regional distribution out through 
zones K and M. Whether there is some intermediate zone between 58.8 and 166.7 km. which 
would give as good results as the local distribution could be determined only by further computa¬ 
tions. 

The discussions under other headings in this report show that the cause of the anomalies 
is local to a great extent. We are forced to believe that the anomalies can not be materially 
reduced by any method of regional distribution of the compensation of general application. 
This fact is clearly shown in the preceding tables, for only occasionally is a large local- 
compensation anomaly greatly reduced by a regional method of distributing the compensa¬ 
tion. More often the regional distribution increases the anomaly. 

As stated on page 88, the method employed for the regional distribution is somewhat 
illogical in that the compensation for each topographic feature is not distributed separately, 
but the author believes the above conclusions would not be changed if the ideal method 
were employed. 


Chapter VII. EFFECT OF THE ELEVATION OF THE STATION UPON THE INTENSITY OF 

GRAVITY. 

In computing the correction to the intensity of gravity due to the elevation of a station 
above sea level the well known formula 


c = -0.0003086 H 

was used, c being the correction for height in dynes and H the elevation in meters. 

The constant factor of this formula was not questioned during the investigation until it 
was found that the gravity anomalies were quite different at pairs of stations near each other 
horizontally, but with a considerable difference in elevation. In the United States there are 3 
such pairs of stations and from the report of the International Geodetic Association 9 sets in 
Europe were selected and the Hayford anomalies were computed for each station involved. 
Later it was found that there are 2 pairs in India. 

There are shown in the following table the data for each of the sets. In two cases there 
are three stations in a set. 

The density is given for information only. Its value is taken from reports of the Inter¬ 
national Geodetic Association. The corrections for topography and isostatic compensation are 
all based on the same density, 2.67. 


Sets of adjacent stations having great differences of elevation. 


Sets of stations 


. fStilfserjoch, Austria. 

l \Franzenhohe, Austria... 

.JSchneekoppe, Germany. 
"(Alter Bruch, Germany.. 

Brocken, Germany. 

qScharfenstein, Germany, 

.fNaye, Switzerland. 

*\Villeneuve, Switzerland. 

(JChaumont, Switzerland. 
^fNeuenburg, Switzerland 


[Gomergrat, Switzerland 
6-lRiffelberg, Switzerland. 
(Zermatt, Switzerland... 

-fBelalp, Switzerland_ 

'\Brig, Switzerland. 


ishorn, Switzerland. 
Fiesch, Switzerland.... 




Sanetsc-h, Switzerland 
Gsteig, Switzerland... 


lf JPikes Peak, Colo. 

lw \Colorado Springs, Colo, 



ai, Ariz. 

Canyon, Ariz 


,,/Cloudland, Tenn. 

^(Hughes, Tenn. 

(Mussoorie (Camels Back), India 

13< Raipur, India. 

iDehra Dun, India. 

,, (Yercaud, India. 

(Salem, India. 


Latitude 

Longitude 

H 

Density 

o-g* 

Hayford 

anomaly, 

1912 

o / 

46 31.8 

O / 

10 27.4 

Meters. 

2760 

2.4 

-0.010 

-0.018 

46 32.0 

10 29.0 

2188 

2.4 

- .014 

- .022 

50 44.2 

15 44.6 

1605 

2.73 

+ .029 

+ .021 

50 45.7 

15 44.6 

917 

2.65 

+ .019 

+ .011 

51 48.0 

10 37 

1140 

2.6 

+ .053 

4- .045 

51 50.0 

10 36.0 

623 

2.6 

+ .052 

4- .044 

46 26.0 

6 58.7 

1987 

2.7 

+ .026 

4- .018 

46 24.1 

6 55.7 

376 

2.6 

+ .019 

4- .011 

47 01.4 

6 57.1 

1018 

2.7 

+ .044 

+ .036 

47 00.1 

6 57.3 

487 

2.7 

+ .032 

+ .024 

45 59.0 

7 46.8 

3016 

2.73 

4- .053 

+ .045 

45 59.6 

7 45.3 

2566 

2.74 

+ .055 

+ .047 

46 01.5 

7 45.0 

1603 

2.76 

+ .044 

4- .036 

46 22.9 

7 59.6 

2132 

2.65 

4- .010 

+ .002 

46 19.7 

8 00.4 

683 

2.72 

- .004 

- .012 

46 25.2 

8 06.8 

2187 

2.65 

4- .013 

+ .005 

46 24.2 

8 08.1 

1049 

2.65 

.000 

- .008 

46 19.3 

7 17.2 

2041 

2.70 

+ .020 

4- .012 

46 23.2 

7 16.2 

1185 

2.63 

+ .021 

+ .013 

38 50.3 

105 02.0 

4293 

2.62 

+ .029 

4- .021 

38 50.7 

104 49.0 

1841 

2.4 

+ .001 

- .007 

36 03.9 

112 07.1 

2179 


4- .009 

+ .001 

36 05.3 

112 06.8 

849 


- .002 

- .010 

36 06.2 

82 07.9 

1890 


+ .012 

4- .004 

36 08.5 

82 07.2 

994 

. 

- .021 

- .029 

30 27.6 

78 04.5 

2110 

(2.8) 

+ .055 

4- .047 

30 24.2 

78 05.8 

1012 

2.5 

+ .027 

4- .019 

30 19.5 

78 03.2 

682 

2.45 

4- .006 

- .002 

11 46.9 

78 12.5 

1369 

2.7 

- .031 

- .039 

11 40.1 

78 09.2 

289 

2.6 

- .048 

- .056 


93 





























































94 


t T . S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


The following table shows the difference in elevation of the stations forming a set and 
the differences in the anomalies for each set. There are two cases where there are three 
stations in a set. In one case (set No. 6) the mean of the two high stations was used in 
getting the differences in elevation and anomaly and in the other case (set No. 13) the mean of 
the two low stations was used: 


Differences of elevations and anomalies for sets of near stations. 


Difference 
of elevation 
high—low 

Difference 
of anomalies 
high—low 

Set No. 

Difference 
of elevation 
high—low 

Difference 
of anomalies 
high—low 

Meiers. 

572 

Dynes. 

+0.004 

9. 

Meters. 

856 

Dynes. 
-0.001 

688 

+ .010 


2452 

+ .028 

517 

+ .001 


1330 

+ .011 

1611 

+ .007 

12. 

896 

+ .033 

531 

+ .012 


1263 

+ .039 

11SS 

+ .010 


1080 

+ .017 

1449 

1138 

+ .014 
+ .013 

Total. 

15571 

+ .198 


It is seen that in only one case is the difference in anomaly negative, and this difference is 
only 0.001 dyne. On an average a difference in elevation of 100 meters causes a difference in 
Ihe anomalies of 0.0013 dyne; and a difference of anomaly of 0.0010 djme is caused by a difference 
in elevation of 79 meters. 

If a change of 0.0000130 in the constant term of the height formula were made, the resulting 
formula, c=— 0.0002956 II, would make the total difference in the anomalies with regard to 
sign equal to zero. 

The derivation of the constant term of the formula from the observed value of gravity at 
124 stations in the United States made its value 0.0003066, with a probable error of ±0.0000017. 
That the height formula is in error by such an amount as the 0.0000130 indicated by the above 
data is improbable for two reasons: First, because if the changed height formula were used in 
computing the correction for elevation for the United States stations, there would be a strong 
relation between the elevation of the stations and the gravity anomaly. The higher the station 
the less algebraically would be its anomaly, while with the unchanged formula there is no 
apparent relation between the anomalies and the elevation. Second, a very careful and thorough 
investigation was made by W. D. Lambert, of the Survey, which failed to disclose any flaws 
in the derivation of the constant factor of the formula. 

An investigation of the subject along other lines was made, and it was found that there are 
several causes to which may be due some of the difference in the anomalies at high and low 
stations which are horizontally close together. 

First. In general the higher station of a pair is on a mountain peak which has comparatively 
steep slopes. The corrections for topography were computed by the zone method, the average 
elevation in the zone being used in the computations. This has the effect of lessening the effect 
of the closer part of the topography in the zone, as the leveling method involved in assuming a 
uniform average level for the whole zone lowers the nearby topography and increases its distance 
from the station. A test was made of the effect of using narrower zones from the station out, 
to a distance of 2.29 km. The tables for these zones are shown on pages 11 to 18. When the 
effect of the topography near the high station was computed with the narrower zones for sta¬ 
tion Pikes Peak, a difference of 0.0033 dyne was found. At station Yavapai, Ariz., the 
difference was found to be 0.0031. The sign of this difference is such as to bring the two 
anomalies for a pair of stations nearer together. 

Second. It may be assumed that in general the higher station of a pair is on topography of 
greater density than the lower one. The former is usually on a mountain peak which is com¬ 
posed of well-compacted matter, while the lower station is in a valley or in the foothills, where 
the material is not so well compacted and has much more porosity than the higher mountain 
mass. It is sometimes true that the two stations of a pair are on different geologic formations. 
'The higher station in general is on the older formation with a greater density. 








































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


95 


If it is assumed that the high station is on topography which has a density 0.10 greater 
than the assumed normal (2.67) and that the lower station is on material 0.10 less than normal, 
and that these densities obtain for all the topography above sea level, then the topography for 
the area near the high station would have a greater effect than that which has been used in tills 
investigation, and, conversely, the topography at the lower station would have a less effect 
than normal. 

This is shown in a clear manner by making the changes in density at Pikes Peak and Colo¬ 
rado Springs. The change in the effect of the topography within a radius of 3.5 km. due to 
increasing its density 0.10 is +0.0085 dyne, while the change from decreasing the density at 
Colorado Springs by 0.10 is —0.0057. The sum of the two changes in topographic effect is 
+ 0.014. The difference between the anomalies at these two stations is 0.028 dyne. The changes 
in density in the topography near each of the stations reduced by one-half the difference between 
the anomalies. The changes at the two stations Cloudland and Hughes would be + 0.0054 and 
— 0.0035, respectively, and the difference of the anomalies at the two stations would be reduced 
from 0.033 to 0.024. 

In practically all cases the difference in the existing anomalies at two close stations, as shown 
in the table on page 93, would be reduced by increasing the density of the topography at the 
high station and decreasing the density of the topography at the low one. The only exception 
to this general rule is pair No. 9 in the above table. Here the lower station has the larger 
anomaly, but the difference between the two anomalies is only 0.001 dyne. 

It is scarcely possible to make a correction for erroneous density of topography used in 
the regular reductions, for even if the density of the surface rocks were known one would not 
be justified in assuming that the density of the surface obtained to any given depth below the 
surface. 

Third. Another correction could be applied to the combined effect of topography and 
compensation at a station which would make the difference smaller between the anomalies at 
a pair of stations close together horizontally but with different elevations. In making the tables 
for computing the effect of topography and compensation it was assumed that the compensa¬ 
tion began at the surface and extended to a depth of 113.7 km. This was done to facilitate 
the computation, although it does not seem to be a reasonable assumption. It is more prob¬ 
able that the compensation begins at sea level or at some lower depth. If it is assumed that 
the compensation begins at sea level, then the effect of compensation for the topography near 
the station above sea level is less than when computed by the usual method. 

If the average elevation of the topography in a near zone is 1900 meters (6200 feet), then 
the change in the effect of the compensation will be one-sixtieth of the effect of the topography 
in that zone. The approximate general rule is that the effect of compensation of topography 
near the station will be reduced by an amount equal to the product of the elevation of a zone 
by the correction for topography for the zone divided by the depth of compensation. 

Let us apply this at Pikes Peak. The elevations for zones C, D, E, and F are, respectively, 
4300, 4100, 3900, and 3700 meters. The corrections for topography for those zones are, respec¬ 
tively, + 0.0165, +0.0325, +0.0545, and +0.0639 dyne. The change in the compensation for 
the four zones is 0.008, and this is the amount the effect of compensation at Pikes Peak is 
reduced. There would be a further reduction in the compensation if the test were made for 
a few zones beyond zone F. The effect of the change at a single station becomes zero in gen¬ 
eral at about zones J or K. For the outer zones the effect is small for any one station and for 
a pair of stations the effect on the relative anomaly is negligible. 

At Colorado Springs, the lower station of the pair, the average elevation of the topography 
out to the limits of zone F is about 1800 meters, and the change in the effect of compensation by 
having it distributed from sea level for zones A to F is 0.002 dyne. The total effect on the 
difference in the anomalies of changing the position of the upper surface of the compensation 
at Pikes Peak and Colorado Springs would be about 0.010 dyne. The reduction of the differ¬ 
ences at other pairs of stations in this country and abroad would be less than this, in most 
cases much less. 


96 


TJ. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


If the depth of compensation were materially reduced, say, to 60 km., then the effect of 
starting the distribution of the compensation at the sea level rather than at the surface would 
he about double what it would be for the depth 113.7 km. 

The table on pages 103-105 shows that if the depth of compensation were 127.9 km. the 
difference in the anomalies at Pikes Peak and Colorado Springs would be reduced to 0.026 dyne, 
and it would he further reduced to 0.021 dyne if the depth were 184.6 km. If the depth were 
42.6 km., the difference in the anomalies at those stations would be increased to 0.051 dyne. For 
85.3 km. it would be 0.033 dyne. A change in the depth makes practically no change in the 
difference between the anomalies at the pair of stations Cloudland and Hughes. The discus¬ 
sion on page 111 indicates that a depth greater than 130 km. is very improbable. 

If the compensation has a regional distribution rather than a local distribution, then the 
anomaly will he reduced at Pikes Peak, it will remain about the same at Colorado Springs, and 
the difference in the anomalies at the two stations will be considerably reduced. If the distri¬ 
bution of compensation is regional to the outer limit of zone O (167 km.), the difference in the 
anomalies will be reduced from 0.028 to 0.012 dyne. It would be 0.016 dyne for regional dis¬ 
tribution to the outer limit of zoneM (59 km.). The regional distribution of the compensation 
does not materially reduce the difference in anomalies for the pair of stations Cloudland and 
Hughes and for the pair Yavapai and Grand Canyon. The effect of regional distribution at 
the pairs of stations not in the United States has not been computed. On page 91 it is shown 
that the regional distribution of the compensation to a distance of 167 km. is not so probable 
as the regional distribution to a much shorter distance or as the local distribution of the com¬ 
pensation. 

We may conclude that the systematic difference in the anomalies at a pair of stations 
close together, with one high and one low station, is not due to error in the height formula nor 
to error in the assumed depth of compensation, but that it is due in part to errors in the assumed 
densities of the topography under the stations, to deviations from the normal densities in the 
material below sea level and in the upper crust, to the use of wide zones in computing the effect 
of the topography, to the probably erroneous assumption that the compensation begins at the 
surface of the topography, and to the assumption of local distribution of the compensation. 
That the cause is located in the upper crust rather than in the lower crust is evident from the 
fact that any deviation from the normal conditions in the lower crust would affect each of the 
two stations of a pair equally, or very nearly so. It is probable that the effect of any one of 
these causes varies considerably for the different pairs. It would be impossible to arrive at 
the true effect of each one of the causes for any pair except the effect of the use of the wide 
zones. The difference in the anomalies is probably due to the combined effect of all of the 
causes. 


Chapter VIII.—EFFECT ON THE INTENSITY OF GRAVITY OF CHANGES IN THE DEPTH 

OF COMPENSATION. 


On pages 103 to 105 of Special Publication No. 10 , “The effect of topography and isostatic 
compensation on the intensity of gravity,” is a discussion of some preliminary tests of the 
effect of a change in the assumed depth of compensation on the gravity anomalies. The con¬ 
clusion reached was that the available gravity stations probably would not determine a depth 
that could compete in accuracy with the depths determined from deflections of the plumb line. 
The further accumulation of material and the further study of the question have brought about 
a partial revision of this conclusion. 

To study the effect of a change in the depth of compensation it is necessary to have the 
effects of topography and isostatic compensation for different depths. To make these compu¬ 
tations with complete theoretic accuracy would require a great amount of labor, even if there 
were available complete sets of tables similar to those on pages 30 to 47 of Special Publication 
No. 10 , but computed for depths other than 113.7 km. This labor was greatly lessened by the adop¬ 
tion of the approximations below. The results of the computations are given on pages 100 - 102 . 

The effect of topography is not altered by a change of depth, but the compensation, and 
therefore the resultant, changes with the changing depth. The method of computation con¬ 
sists in multiplying either the compensation or the resultant of the topography and compen¬ 
sation by a factor depending on the depth and on the zone involved. 

In the tables on pages 30 to 43 of Special Publication No. 10 , the correction for elevation 
of the station above or below the compartment is, strictly speaking, the correction to the com¬ 
bined effect of topography and compensation, but most of the correction is due to the change 
in the effect of the topography and the part due to the change in the effect of the compensation 
is relatively small. The change with changing depth in the part due to compensation will 
generally be smaller still. Neglecting this—that is, considering the compartment to be on the 
same level as the station—the formula for the compensation C is 

C=2ttIl8{c 2 — c 1 — ~Jc 2 2 + t 2 + ■y/cf + t 2 } 


in which fc is the gravitation constant, c x and c 2 are the inner and outer radii of the zone, and t is 
the depth of compensation. 8 is the density of compensation and for land compartments is given 

by the formula, 5 = 2.67 j, where h is the mean elevation of the compartment, the density of the topog- 

raphy being assumed as 2.67. If C 0 denote the compensation for depth 113.7 and C d the compensa¬ 
tor c — c 

tion for any other depth, it is evident that ^ or d - ^ ~ - is independent of h, the elevation of the 

compartment, and also of the assumed density of the topography, and depends only on the two 

depths involved. The quantity —^—- was computed for an arbitrary elevation of comp art- 

ment but applies equally well to any elevation and was so used. It is the factor which multiplied 
by C 0 will give the correction to be added algebraically to C 0 to give C d , the compensation 

C — C 

at the new depth. The values of — 7 = 7 —- for various depths of compensation are shown in the 


Co 


C d -C 0 


following tables for zones A to O. In interpolating values of —^ for depths near 113.7 km 

C — C 

should be remembered that ■ d q ° is zero for this depth. 


it 


59387°—17- 


97 









98 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Factors, 


C d -C 0 

Co 


, used in computing compensation for the given depths. 


Zone 

Factors for depth of compensation of— 

42.6 km. 

56.9 km. 

85.3 km. 

127.9 km. 

156.25 km. 

184.6 km. 


+1.67 

+ 1.00 

+0.33 

-0.11 

-0.27 

-0.38 


+ 1.87 

+ 1.00 

+ .33 

- . 11 

- .27 

- .38 


+ 1.66 

+ 1.00 

+ .33 

- . 11 

- .27 

- .38 


+ 1.65 

+1.00 

f .33 

- . 11 

- .27 

- .38 


+ 1.63 

+ . 9S 

+ .33 

- . 11 

- .27 

- .38 


+1.60 

+ .97 

+ .33 

- .11 

- .27 

- .38 


+ 1.55 

+ .95 

+ .32 

- .11 

- .26 

- .38 


+ 1.49 

+ .92 

+ .32 

- .11 

- .26 

- .37 


+ 1.39 

+ .87 

+ .31 

- .10 

- .26 

- .37 


+1.24 

+ .80 

+ .29 

- .10 

- .25 

- .36 


+1.03 

+ .70 

-f- . 2/ 

- .10 

- .24 

- .35 

L. 

~b . /3 

+ .55 

+ .23 

- .09 

- .22 

- .32 


+ .22 

+ .24 

+ .14 

- .06 

- . 17 

- .26 


- .23 

- .10 

.00 

- .02 

- .07 

- .14 


- .45 

- .31 

- . 11 

+ .03 

+ .06 

+ .05 


The factors in this table were also applied to ocean compartments, although the com¬ 
pensation which begins at the bottom of the ocean is never on the same level as the station. 
The error, however, is not large. For ocean compartments the density is 0.615 times that of a 
land compartment when the height of the land is equal to the depth of the ocean compartment. 
The sign of the density is reversed. 

For the outer zones, numbers 1 to 18, a correction factor is applied to the resultant effect, 
R, of the topography and compensation. This resultant is proportional to the elevation of the 
compartment, or 

R — pii * 


in which h is the elevation of the compartment and p is a factor of proportionality given in the 
tables in Special Publication No. 10, and there computed by the method of quadratures.! If a 
subscript zero denote the values of R and p for depth 113.7 Ion., and the same letters with 
subscript d the corresponding quantities for another depth, then 


R d Ro _ pd Po 

Ro ~ po 


or the correction factor, 


Rd ~~ Ro 


is independent of the height of the compartment, though for con¬ 


venience in computing a standard height was assumed. The values of this factor for various 
depths are given in the following table. The factors are to be multiplied by the resultant of the 
topography and compensation for depth 113.7 km. in the same way as the factors in the pre¬ 
ceding table are to be multiplied by the compensation and give the correction to be added 
algebraically to the resultant for the depth 113.7 km. to obtain the resultant for the particular 
depth in question. 


* The corrections for departures from proportionality and for elevation of station which occur in zones 14-18 are neglected as unimportant, 
t The resultant might have been found mathematically by integration, but this was not discovered until Special Publication No. 10 was in 
press. The formula of integration and the tables for its use (based on zones different from those used by the Coast and Geodetic Survey) are given 
by G. Cassinis in publication entitled “Sull ’Applicazione del Metodo Isostatico alle Riduzione delle Misure di Gravita,” Rome, 1911. In 
computing the density of compensation of his outer zones I to XX, Cassinis neglects the convergence of the verticals bounding the compensation, 
and his density of compensation should be multiplied by approximately 1.019. Although this error is less than 2 per cent of the compensation, 
since topography and compensation are large and nearly equal for distant zones, it completely falsifies the resultant for these zones. This error 
is repeated in the publication by Reina and Cassinis, “ Determinazione di Gravita Relativa compiute nel 1912 a Roma, Arc6tri, Livorno, Genova, 
Vienna e Potsdam,” Rome, 1913. This error was corrected before use was made in this publication of the computed reductions for topography 
and isostatic compensation given in the publication just mentioned. (See p. 57.) 

In Gerland’s “Beitriige zur Geophysik” Band XII, pp. 588-638, there is an extended discussion of formulas by Erich Hiibner entitled, ‘‘Beitrag 
zur Theorie der isostatischen Reduktion der Schwerebeschleunigungen.” On p. 638 he notes an error of 2 per cent in the tables of Special Publi¬ 
cation No. 10, due to neglecting the convergence of the verticals. This error is, however, 2 per cent of the small resultant for any compartment, not 
2 per cent of the compensation, and may, therefore, be neglected. 







































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


99 


Factors, 


Rd ~ Ro 

R 0 


, used in computing resultant of topography and compensation for given depths. 


Zone 


Factors for depth of compensation of— 


42.6 km. 

56.9 km. 

85.3 km. 

127.9 km. 

156.25 km. 

184.6 km. 

18. 

-0.53 

-0.41 

-0.17 

+0.06 

+0.14 

+0.19 

17. 

- .56 

- .42 

- .18 

+ .07 

+ .18 

+ .24 

16. 

- .57 

- .43 

- .19 

+ .08 

+ .21 

+ .30 

15. 

- .58 

— .45 

- .21 

+ .09 

+ .24 

+ .36 


- .59 

- .46 

- .22 

+ .10 

+ .27 

+ .41 


- .61 

- .47 

- .23 

+ .11 

+ .30 

+ .48 


- .62 

- .49 

- .24 

+ .12 

+ .34 

+ .54 


- .62 

- .49 

- .24 

+ .12 

+ .35 

+ .57 


- .62 

- .50 

- .24 

+ .13 

+ .36 

+ .59 


- .62 

- .50 

- .24 

+ .13 

+ .37 

+ .62 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

— .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


- .63 

- .50 

- .25 

+ .13 

+ .38 

+ .63 


An example of the use of these tables is given below. The quantities in the second and 
third columns are taken from page 42 and are multiplied by the factors in the tables on page 98 
and above and the products are placed in the appropriate column. The total of these products 
for a given depth is the correction to be applied to the effect of topography and isostatic com¬ 
pensation for depth 113.7 km. in order to obtain the effect for the depth in question. 

In the same way the computations for other stations in the United States have been made, 
and the results to three decimals of dynes are shown on pages 100-102. 

Corrections for change of depth, station 195, Lander, Wyo. 

[These corrections are in units of the fourth decimal place in dynes and are to be added algebraically to the effects of topography and compensation 

for the depth 113.7 km. to obtain the effects at other depths.] 


A. 

B. 

C. 
D 

E. 

F. 

G. 

H 

I. 

J. 

K 

L. 

M 

N. 

O. 

18 

17. 

16. 

15. 

14. 

13. 

12 

11 

10 . 

9.. 

8 .. 

7.. 

6 .. 

5.. 

4.. 

3.. 

2 .. 

1 .. 


Zone 


Total topography and compensation, 113.7 km. 

Total topography and compensation at given depth 


Result- 
Compen- ant, to- 
sation pography 


Correction for depth- 


only 113.7 andeom- 
km. pensation 
113.7 km. 


0 

0 

- 4 

- 6 
- 8 

- 20 

- 24 

- 32 

- 43 

- 66 


-109 

-158 

-425 

-373 

-341 


- 68 
- 68 

- 71 

- 66 
- 61 

- 88 

- 51 

- 37 

- 17 

0 

+ 8 
+ 7 
+ 9 
+ 9 
+ 8 

+ 5 
+ 3 
+ 1 


42.6 km. 

56.9 km. 

85.3 km. 

127.9 km. 

156.25 km. 

184.6 km. 


0 


0 


0 


0 


0 


0 


0 


0 


0 


0 


0 


0 

— 

7 

— 

4 

— 

1 


0 

+ 

1 

+ 

2 

— 

10 

— 

6 

— 

2 

+ 

1 

+ 

2 

+ 

2 


13 


8 

— 

3 

+ 

1 

+ 

2 

+ 

3 

_ 

32 

_ 

19 

_ 

7 

+ 

2 

+ 

5 

+ 

8 

— 

37 

— 

23 

— 

8 

+ 

3 

+ 

6 

+ 

9 

_ 

4'8 

— 

29 

— 

10 

+ 

4 

+ 

8 

+ 

12 

_ 

60 

— 

37 

— 

13 

+ 

4 

+ 

11 

+ 

16 

— 

82 

— 

53 

— 

19 

+ 

7 

+ 

16 

+ 

24 


112 

_ 

76 

_ 

29 

+ 

11 

+ 

26 

+ 

38 


115 

— 

87 

— 

36 

+ 

14 

+ 

35 

+ 

51 

_ 

94 


102 

— 

60 

+ 

26 

+ 

72 

+ 110 

+ 

86 

rh 

37 


0 

4* 

7 

+ 

26 

+ 

52 

+ 153 

+ 106 

+ 

37 

— 

10 


20 

— 

17 


36 

+ 

28 

+ 

12 

— 

4 

— 

10 

— 

13 

+ 

38 

+ 

29 

+ 

12 

— 

5 

— 

12 

— 

16 

+ 

40 

+ 

31 

+ 

14 

— 

6 

— 

15 

— 

21 

+ 

38 

*4" 

30 

+ 

14 

— 

6 

— 

16 

— 

24 

+ 

36 

+ 

28 

+ 

13 

— 

6 

— 

16 

— 

25 

+ 

54 

•K 

41 

+ 

20 

— 

10 

— 

26 

— 

42 

+ 

32 

+ 

25 

+ 

12 

— 

6 

— 

17 

— 

28 

+ 

23 

+ 

18 

+ 

9 

— 

4 

— 

13 

— 

21 

+ 

11 

+ 

8 

+ 

4 

— 

2 

— 

6 

— 

10 

0 


0 


0 


0 


0 


0 


5 

_ 

4 

— 

2 

+ 

1 

+ 

3 

+ 

5 

_ 

4 

— 

4 

— 

2 

+ 

1 

+ 

3 

+ 

4 

_ 

6 

_ 

4 

— 

2 

+ 

1 

+ 

3 

+ 

6 

_ 

6 

_ 

4 

— 

2 

+ 

1 

+ 

3 

+ 

6 

— 

5 

— 

4 

— 

2 

+ 

1 

+ 

3 

+ 

5 

_ 

3 

_ 

2 

_ 

1 

+ 

1 

+ 

2 

+ 

3 

_ 

2 

_ 

2 

— 

1 


0 

+ 

1 

+ 

2 

- 

1 


0 


0 


0 


0 

+ 

1 


95 


87 

_ 

53 

+ 

27 

+ 

77 

+ 142 


275 


275 


275 

_ 

275 


275 


275 


370 


362 


328 


248 


198 


133 
















































































































100 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40 


The following table gives the effect of topography and compensation for each of the 219 
stations in the United States for various depths. 

Corrections for topography and isostatic compensation for given depths of compensation. 


Number and name of station 


Depth, 
42.6 km. 


Depth, Depth, 
56.9 km. 85.3 km. 


1. Key West, Fla. 

2. West Palm Beach, Fla 

3. Punta Gorda, Fla. 

4. Apalachicola, Fla. 

5. New Orleans, La. 


+0.017 
+ .016 
+ .008 
+ .006 
+ .005 


+0.022 
+ .019 
+ .010 
+ .008 
+ .007 


+0.029 
+ .025 
+ .016 
+ .012 
+ .010 


Depth, 
113.7 km. 


+0.035 
+ .031 
+ .020 
+ .015 
+ .013 


Depth, 
127.9 km. 


+0.038 
+ .033 
+ .023 
+ .017 
+ .015 


Depth, 
156.25 km. 


+0.043 
+ .038 
+ .027 
+ .020 
+ .017 


Depth, 
184.6 km. 


+0.047 
+ .043 
+ .031 
+ .023 
+ .020 


6. Rayville, La. 

7. Galveston, Tex. 

8. Point Isabel, Tex. 

9. Laredo, Tex. 

10. Austin, Tex. (capitol) 


+ .005 
+ .003 
+ .007 
+ .004 
- .005 


+ .005 
+ .004 
+ .009 
+ .005 
- .005 


+ .006 
+ .006 
+ .013 
+ .003 
- .004 


+ .008 
+ .007 
+ .015 
+ .003 
- .003 


+ .008 
+ .008 
+ .017 
+ .003 
- .002 


+ .010 
+ .010 
+ .019 
+ .004 
- .004 


+ .011 
+ .011 
+ .021 
+ .006 
.000 


11. Austin, Tex. (university) 

12. McAlester, Okla. 

13. Little Rock, Ark. 

14. Columbia, Term. 

15. Atlanta, Ga. 


- .003 
.000 
+ .003 
+ .003 
+ .008 


- .003 
.000 
+ .002 
+ .003 
+ .009 


- .002 
.000 
+ .001 
+ .004 
+ .012 


- .001 
+ .001 
+ .001 
+ .006 
+ .014 


- .001 
+ .001 
+ .001 
+ .007 
+ .015 


+ .001 
+ .002 
+ .002 
+ .009 
+ .018 


+ .002 
+ .003 
+ .003 
+ .011 
+ .021 


16. McCormick, S. C... 

17. Charleston, S. C... 

18. Beaufort, N. 0. 

19. ( harlottesville, Va. 

20. Deer Park, Md_ 


+ .008 
+ .006 
+ .015 
- .002 
+ .021 


+ .008 
+ .008 
+ .020 
- .002 
+ .026 


+ .009 
+ .012 
+ .028 
.000 
+ . 035 


+ .012 
+ .016 
+ .036 
+ .002 
+ .041 


+ .014 
+ .018 
+ .040 
+ .004 
+ .044 


+ .016 
+ .021 
+ .046 
+ .007 
+ .049 


+ .019 
+ .024 
+ .051 
+ .010 
+ .054 


21. Washington, D. C. (Coast and Geodetic Survey Office) 

22. Washington, D. C. (Smithsonian Institution). 

23. Baltimore, Md. 

24. Philadelphia, Pa. 

25. Princeton, N. J. 


.000 
- .001 
+ .001 
+ .003 
+ .007 


+ .001 
.000 
+ .001 
+ .004 
+ .008 


+ .002 
+ .001 
+ .003 
+ .006 
+ .010 


+ .004 
+ .003 
+ .006 
+ .009 
+ .013 


+ .005 
+ .005 
+ .007 
+ .011 
+ .015 


+ .007 
+ .007 
+ .009 
+ .014 
+ .017 


+ .010 
+ .010 
+ .012 
+ .017 
+ .021 


26. Hoboken N. J... 

27. New York, N. Y 

28. Worcester, Mass. 

29. Boston, Mass_ 

30. Cambridge, Mass 


+ .001 
+ .004 
+ .007 
+ .005 
+ .002 


+ .002 
+ .005 
+ .010 
+ .007 
+ .003 


+ .005 
+ .007 
+ .013 
+ .010 
+ .007 


+ .008 
+ .011 
+ .018 
+ .013 
+ .010 


+ .010 
+ .012 
+ .020 
+ .015 
+ .012 


+ .012 
+ .015 
+ .024 
+ .018 
+ .015 


+ .016 
+ .019 
+ .028 
+ .022 
+ .019 


31. Calais, Me. 

32. Ithaca, N. Y_ 

33. Cleveland, Ohio. 

34. Cincinnati, Ohio. 

35. Terre Haute, Ind 


+ .005 
- .001 
- .002 
+ .001 
.000 


+ .006 
.000 
- .002 
.000 
.000 


+ .008 
+ .002 
- .002 
+ .001 
.000 


+ .010 
+ .005 
.000 
+ .002 
+ .001 


+ .012 
+ .006 
+ .001 
+ .003 
+ .001 


+ .013 
+ .009 
+ .002 
+ .005 
+ .002 


+ .016 
+ .012 
+ .003 
+ .007 
+ .003 


36. Chicago, Ill. 

37. Madison, Wis_ 

38. St. Louis, Mo_ 

39. Kansas City, Mo. 

40. Ellsworth, Kans. 


+ .007 
+ .001 
+ .002 
.000 
- .003 


+ .007 
+ .001 
+ .001 
- .001 
- .004 


+ .006 
+ .002 
+ .001 
- .002 
- .004 


+ .007 
+ .003 
+ .001 
- .001 
- .004 


+ .008 
+ .004 
+ .001 
- .001 
- .004 


+ .009 
+ .005 
+ .002 
- .001 
- .004 


+ .011 
+ .007 
+ .002 
.000 
- .003 


41. Wallace, Kans. 

42. Colorado Springs, Colo 

43. Pikes Peak, Colo. 

44. Denver, Colo. 

45. Gunnison, Colo. 


- .007 

- .024 
+ .147 

- .015 

- .024 


- .006 
- .020 
+ .159 

- .017 

- .021 


- .003 

- .014 
+ .175 

- .018 
- .012 


.000 

- .007 
+ .187 

- .015 

- .001 


+ .001 

- .004 
+ .192 

- .013 
+ .004 


+ .003 
+ .002 
+ .201 
- .009 
+ .013 


+ .006 
+ .010 
+ .211 
- .004 
+ .024 


46. Grand Junction Colo. 

47. Green River, Utah. 

48. Pleasant Valley Junction, Utah. 

49. Salt Lake City, Utah. 

50. Grand Canyon, Wyo. 


- .050 

- .036 

- .002 
- .044 
+ .009 


- .053 

- .040 
+ .004 

- .044 
+ .015 


- .054 

- .043 
+ .014 

- .044 
+ .027 


- .051 

- .043 
+ .024 

- .041 
+ .038 


- .049 

- .043 
+ .028 

- .040 
+ .043 


- .046 

- .041 
+ .035 

- .037 
+ .051 


- .040 

- .038 
+ .042 

- .032 
+ .060 


51. Norris Geyser Basin, Wyo. 

52. Lower Geyser Basin, Wyo. 

53. Seattle, Wash, (university) 

54. San Francisco, Cal. 

55. Mount Hamilton, Cal. 


+ .005 
+ .004 
- .012 
+ .024 
+ .092 


+ .011 
+ .009 
- .015 
+ .029 
+ .100 


+ .021 
+ .018 
- .019 
+ .038 
+ .112 


+ .031 
+ .028 
- .020 
+ .045 
+ .120 


+ .036 
+ .033 
- .021 
+ .048 
+ .124 


+ .044 
+ .040 
- .021 
+ .053 
+ .130 


+ .052 
+ .049 
- .020 
+ .058 
+ .135 


56. Seattle, Wash (high school) 

57. Iron River, Mich. 

58. Ely, Minn. 

59. Pembina, N. Dak. 

60. Mitchell, S. Dak. 


- .009 
+ .006 
+ .004 

- .006 
- .004 


- .013 
+ .008 
+ .005 

- .007 

- .004 


- .017 
+ .011 
+ .007 

- .008 
- .005 


- .018 
+ .014 
+ .008 

- .009 

- .006 


- .018 
+ .016 
+ .009 

- .009 

- .006 


- .018 
+ .018 
+ .010 

- .009 

- .006 


- .018 
+ .020 
+ .012 

- .009 

- .006 


61. Sweetwater, Tex 

62. Kerrville, Tex... 

63. El Paso, Tex_ 

64. Nogales, Ariz_ 

65. Yuma, Ariz. 


+ .003 
+ .003 

- .005 
+ .020 

- .008 


+ .005 
+ .006 

- .004 
+ .025 

- .009 


+ .007 
+ .010 
- .002 
+ .032 
- .010 


+ .009 
+ .013 
+ .001 
+ .038 
- .010 


+ .010 
+ .015 
+ .002 
+ .040 
- .010 


+ .013 
+ .018 
+ .005 
+ .044 
- .009 


+ .015 
+ .021 
+ .009 
+ .049 
- .008 


66. Compton, Cal. 

67. Goldfield, Nev. 

68. Yavapai, Ariz.. 

69. Grand Canyon, Ariz, 

70. Gallup, N. Mex. 


- .005 
+ .006 
+ .016 

- .110 
- .006 


- .004 
+ .012 
+ .020 

- .108 
- .001 


- .002 
+ .019 
+ .027 
- .102 
+ .006 


.000 
+ .027 
+ .034 
- .096 
+ .014 


+ .002 
+ .031 
+ .037 
- .093 
+ .018 


+ .005 
+ .038 
+ .042 
- .088 
+ .024 


+ .009 
+ .046 
+ .050 
- .080 
+ .032 


71. Las Vegas, N. Mex 

72. Shamrock, Tex_ 

73. Denison, Tex. 

74. Minneapolis, Minn. 

75. Lead, S. Dak. 


- .004 
+ .003 

- .002 
- .004 
+ .025 


+ .001 
+ .003 
- .002 
- .005 
+ .031 


+ .009 
+ .005 
- .001 
- .005 
+ .038 


+ .017 
+ .007 
- .001 
- .005 
+ .044 


+ .021 
+ .008 
.000 
- .005 
+ .047 


+ .027 
+ .010 
+ .001 
- .005 
+ .051 


+ .035 
+ .012 
+ .002 
- .004 
+ .055 








































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


101 


Corrections for topography and isostatic compensation for given depths of compensation —Continued. 


Number and name of station 

Depth, 
42.6 km. 

Depth, 1 
56.9 km. 

| 

| 

Depth, 
85.3 km. j 

Depth, 
113.7 km. 

Depth, 
127.9 km. 

Depth, 
156.25 km. 

Depth, 
184.6 km. 

76. Bismarck, N. Dak. 

-0 

.005 

-0 

.005 

-0 

.006 ! 

-0 

.005 

-0 

.005 

-0.005 

-0.004 

77. Hinsdale, Mont. 

— 

.012 

— 

.014 

— 

.015 

— 

.017 

— 

.017 

- .018 

- .017 

78. Sandpoirit Idaho. 

79. Boise, Idaho. 

— 

.042 

— 

.044 

— 

.045 

— 

.044 

— 

.044 

- .042 

- .040 

— 

.035 

— 

.038 1 

— 

.041 

— 

.042 

— 

.042 

- .042 

- .040 

80. Astoria, Oreg. 

+ 

.001 

+ 

.002 

+ 

.005 

+ 

.008 

+ 

.008 

+ .011 

+ .013 

81. Sisson, Cal. 

82. Rock Springs, Wyo. 

83. Paxton, Nebr..... 

_ 

.015 

_ 

.008 

+ 

.004 

+ 

.015 

+ 

.020 

4- .029 

+ .038 

— 

.014 

— 

.011 

— 

.007 


.001 

+ 

.001 

+ .006 

+ .013 


.000 

— 

.001 


.000 


.002 

+ 

.002 

+ .004 

+ .006 

84. Washington, D. C. (Bureau of Standards). 

+ 

.008 

+ 

.008 

+ 

.010 

+ 

.012 

+ 

.013 

+ .015 

+ .018 

85. North liero, Vt. 

— 

.007 

— 

.008 

— 

.009 

— 

.009 

— 

.008 

- .007 

- .005 

86. Lake Placid, N. Y. 

+ 

.014 

+ 

.019 

+ 

.026 

+ 

.032 

+ 

.034 

+ .039 

+ .043 

87. Potsdam, N. Y. 

— 

.007 


.006 


.005 


.004 


.003 

- .001 

+ .001 

88. Wilson, N.Y. 


.000 

— 

.001 

— 

.002 

_ 

.002 

— 

.001 

- . 001 - 

.000 

89. Alpena, Mich. 

— 

.004 

— 

.003 

— 

.002 


.000 


000 

+ .002 

+ .003 

90. Virginia Beach, Va. 

+ 

.010 

+ 

.013 

+ 

.019 

+ 

.025 

+ 

028 

+ .032 

+ .037 

91. Durham, N. C. 

+ 

.009 

+ 

.009 

+ 

.011 

+ 

014 

+ 

016 

+ .019 

+ .022 

92. Fernandina, Fla. 

+ 

.007 

+ 

.009 

+ 

.013 

+ 

017 

+ 

019 

+ .023 

+ .026 

93. Wilmer, Ala. 

94. Aliceville, Ala. 

■j* 

.011 

+ 

.013 

+ 

.016 

+ 

018 

+ 

019 

+ .022 | 

+ .025 

4- 

.006 

+ 

.006 

+ 

.007 

+ 

.008 

+ 

009 

+ .010 

+ .012 

95. New Madrid, Mo. 

+ 

.003 

+ 

.002 

+ 

.001 

+ 

.001 

+ 

001 

+ .001 

+ .002 

96. Mena, Ark. 

+ 

.011 

+ 

.012 

+ 

.013 

+ 

.015 

+ 

015 

+ .017 

+ .018 

97. Nacogdoches, Tex. 

+ 

.007 

+ 

.007 

+ 

.007 

+ 

.008 

+ 

.008 

+ .009 

+ .010 

98. Alpine, Tex. 

99. Farwell, Tex. 

+ 

.013 

+ 

.017 

+ 

.025 

+ 

.033 

+ 

.036 

+ .042 

+ .048 

+ 

.003 

+ 

.005 

+ 

.008 

+ 

.011 

+ 

.013 

+ .016 

+ .021 

100. Guymon, Okla. 

— 

.003 


.004 

— 

.003 


.001 


.000 

+ .002 

+ .005 

101. Helen wood, Term. 

+ 

.005 

+ 

.007 

+ 

.011 

+ 

.015 

+ 

.017 

+ .020 

+ .024 

102. Cloudland, Tenn. 

+ 

.102 

+ 

.109 

+ 

.121 

+ 

.130 

+ 

.134 

+ .141 

+ .147 

103. Hughes, Tenn. 

+ 

.026 

+ 

.033 

4- 

.044 

+ 

.053 

+ 

.056 

+ .063 

+ .069 

104. Charleston, W. Va. 

— 

.011 

— 

.012 

— 

.011 

— 

.010 

— 

.009 

- .007 

- .004 

105. State College, Pa. 

+ 

.002 

+ 

.003 

+ 

.006 

+ 

.010 

+ 

.012 

+ .015 

+ .019 

106. Fort Kent, Me. 


.000 


.000 


.000 

+ 

.001 

+ 

.002 

+ .003 

+ .005 

107. Prentice, Wis. 

+ 

.003 

+ 

.005 

+ 

.008 

+ 

.010 

+ 

.011 

+ .013 

+ .015 

108. Fergus Falls, Minn. 

+ 

.002 

+ 

.001 

+ 

.001 

+ 

.001 

+ 

.001 

+ .001 

+ .002 

109. Sheridan, Wyo. 


.035 

— 

.036 

— 

.034 


.031 

— 

.029 

- .025 

- .021 

110. Boulder, Mont. 

— 

.022 

— 

.019 

— 

.013 

— 

.007 

— 

.005 

.000 

+ .006 

111. Skykomish, Wash. 

_ 

.063 

_ 

.059 

_ 

.053 

_ 

.047 

_ 

.045 

- .041 

- .037 

112. Olympia, Wash. 

— 

.008 

— 

.010 

— 

.012 

— 

.012 

— 

.011 

- .011 

- .009 

113. Heppner, Oreg. 

— 

.005 

— 

.006 

— 

.007 

— 

.007 

— 

.006 

- .005 

- .004 

114. Truekee,Cal. 

+ 

.014 

+ 

.025 

+ 

.043 

+ 

.057 

+ 

.064 

+ .074 

+ .085 

115. Winnemucca, Nev. 


.008 


.009 

_ 

.007 

— 

.004 

— 

.002 

+ .002 

+ .008 

116. Ely, Nev. 

_ 

.007 

_ 

.001 

+ 

.010 

+ 

.020 

+ 

.025 

+ .033 

+ .041 

117. Guernsey, Wyo. 

— 

.015 

— 

.017 


.018 

— 

.016 

— 

.015 

- .013 

- .010 

118. Pierre. S'. Dak. 

— 

.009 

— 

.010 

— 

.012 

— 

.013 

— 

.013 

- .014 

- .014 

119. Fort Dodge, Iowa. 

+ 

.002 

+ 

.002 

+ 

.001 

+ 

.002 

+ 

.002 

+ .002 

+ .004 

120. Keithsburg, Ill. 

— 

.005 

— 

.005 


.003 

— 

.003 

— 

.002 

- .002 

- .001 

121. Grand Rapids, Mich. 

+ 

.001 

+ 

.001 

+ 

.002 

+ 

.003 

+ 

.004 

+ .005 

+ .006 

122. Angola, Ind. 

+ 

.008 

+ 

.008 

+ 

.010 

+ 

.011 

+ 

.012 

+ .014 

+ .015 

123. Albany, N.Y. 


.010 

— 

.010 


.009 

— 

.006 

— 

.004 

— .001 

+ .002 

124. Port Jervis, N.Y. 

— 

.008 

— 

.006 

— 

.002 

+ 

.003 

+ 

.005 

+ .009 

+ .013 

125. Atlantic City, N. J. 

+ 

.007 

+ 

.010 

+ 

.014 

+ 

.018 

+ 

.021 

+ .024 

+ .028 

126. Bridgehampton, N. Y. 

+ 

.008 

+ 

.011 

+ 

.016 

+ 

.020 

+ 

.022 

+ .026 

+ .030 

127. Chatham, Mass. 

+ 

.010 

+ 

.014 

+ 

.019 

+ 

.024 

+ 

.027 

+ .031 

+ .036 

128. Rockland, Me. 

+ 

.004 


.006 

+ 

.008 

4" 

.011 

+ 

.012 

+ .014 

+ .017 

129. Lancaster, N. H. 


.006 

— 

.003 

+ 

.002 

+ 

.007 

4- 

.009 

+ .013 

+ .017 

130. Whitehall, N.Y. 

— 

.017 

— 

.016 

— 

.015 

— 

.012 

— 

.011 

— .008 

- .004 

131. Little Falls, N. Y. 

_ 

.014 

_ 

.013 


.010 

— 

.007 

— 

.005 

- .001 

+ .003 

132. Watertown, N. Y. 

— 

.002 

— 

.002 


.001 

+ 

.001 

+ 

.002 

+ .004 

+ .005 

133. Southport, N. Y. 

— 

.007 

— 

.005 


.000 

+ 

.004 

+ 

.006 

+ .010 

+ .014 

134. Erie, Pa. 

_ 

.002 

— 

.001 


.000 

+ 

.001 

+ 

.002 

+ .003 

+ .005 

135. Parkersburg, W. Va. 

— 

.010 

— 

.009 

— 

.008 

— 

.006 

— 

.005 

- .003 

.000 

136 . Columbus, Ohio. 

_ 

.002 

_ 

.002 


.001 

+ 

.001 

+ 

.002 

+ .004 

+ .006 

137. Indianapolis. Ind. 

— 

.001 


.000 

+ 

.002 

+ 

.003 

+ 

.004 

+ .006 

+ .007 

138. Springfield, Ill. 

+ 

.004 

+ 

.004 

+ 

.004 

+ 

.005 

+ 

.005 

+ .006 

+ .006 

139. Lebanon, Mo. 

+ 

.007 

+ 

.008 

+ 

.010 

+ 

.012 

+ 

.012 

+ .014 

+ .016 

140. Joplin, Mo. 


.002 


.001 


.000 

+ 

.001 

+ 

.001 

+ .003 

+ .004 

141. Fort Smith, Ark. 

_ 

.006 


.007 


.008 

_ 

.007 

— 

.007 

- .006 

- .005 

142. Texarkana, Ark. 

+ 

.001 

+ 

.001 


.000 

+ 

.001 

+ 

.001 

+ .002 

+ .002 

143. Hot Springs, Ark. 

+ 

.002 

+ 

.002 

+ 

.003 

+ 

.004 

+ 

. 005 

+ .006 

+ .008 

144. Alexandria, La. 

+ 

.005 

+ 

.006 

1 + 

.008 

+ 

.009 

+ 

.010 

+ .012 

+ .013 

145. Laurel, Miss.. 

+ 

.005 

+ 

.006 

+ 

.009 

4* 

.011 

4* 

.013 

+ .015 

+ .017 

146. Richmond, Va. 

+ 

.004 

+ 

.005 

+ 

.007 

+ 

.010 

+ 

.011 

+ .014 

+ .017 

147. Emporia, Va. 

+ 

.007 

+ 

.009 

+ 

.012 

+ 

.015 

+ 

.017 

+ .020 

+ .023 

148. Greenville, N. C. 

+ 

.008 

+ 

.010 

+ 

.015 

4- 

.019 

+ 

.021 

+ .025 

+ .029 

149. Wilmington, N. C. 

+ 

.010 

+ 

.013 

+ 

.018 

+ 

.023 

+ 

.026 

+ .030 

+ .035 

150. Cheraw, S.C. 

+ 

.006 

+ 

.007 

+ 

.010 

+ 

.013 

+ 

.014 

+ .017 

+ .021 

151. Charlotte, N. C. 

+ 

.006 

+ 

.008 

+ 

.011 

+ 

. 015 

+ 

.016 

+ .020 

+ .024 

152. Asheville' N. C. 

+ 

.004 

+ 

.009 

+ 

.018 

+ 

.026 

+ 

.029 

•f* . 0t5D 

+ .041 

153. Cleveland, Tenn. 


.006 


.004 

— 

.001 

+ 

.002 

+ 

.003 

+ .006 

+ .009 

154. Winston-fSalem, N. C. 

+ 

.003 

+ 

.005 

+ 

.009 

+ 

.012 

+ 

.014 


+ . 021 

155. Knoxville, Tenn..... 


.007 

— 

.006 

— 

.004 

— 

.001 


.000 

+ .003 

+ .006 




















































































































102 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Corrections for topography and isostatic compensation for given depths of compensation —Continued. 


Number and name of station 

Depth, 
42.6 km. 

Depth, 
56.9 km. 

Depth, 
85.3 km. 

Depth, 
113.7 km. 

Depth, 
127.9 km. 

Depth, 
156.25 km. 

Depth, 
184.6 km. 

156. Bristol, Va. 

-0 

.002 

+0 

.001 

+0 

.007 

+0 

.012 

+C 

.014 

+c 

.019 

+0.024 

157. Homestead, Fla. 

4" 

.013 

4" 

.016 

+ 

.024 

+ 

.029 

+ 

.032 

4- 

.037 

+ 

.042 

158. Sebring, Fla. 

■f 

.010 

+ 

.013 

+ 

.018 

+ 

.023 

+ 

.025 

4- 

.030 

+ 

.034 

159. Titusville, Fla. 

+ 

.009 

+ 

.012 

+ 

.018 

+ 

.023 

+ 

.025 

+ 

.030 

+ 

.034 

160. Leesburg, Fla. 

+ 

.009 

+ 

.012 

4" 

.016 

+ 

.021 

+ 

.023 

+ 

.027 

+ 

.031 

161. Cedar Keys, Fla. 

+ 

.006 

+ 

.008 

+ 

.012 

4- 

.016 

+ 

.018 

+ 

.022 

+ 

.025 

162. Macon, Ga. 

+ 

.001 

+ 

.002 

+ 

.004 

+ 

.007 

+ 

.008 

+ 

.010 

+ 

.013 

163. Albany, Ga. 

+ 

.004 

+ 

.005 

4" 

.008 

4- 

.011 

4~ 

.012 

+ 

.015 

+ 

.018 

164. Pensacola, Fla. 

*4" 

.005 

+ 

.007 

+ 

.010 

+ 

.014 

+ 

.015 

+ 

.018 

+ 

.020 

165. Opelika, Ala. 

+ 

.007 

4" 

.009 

+ 

.013 

+ 

.017 

+ 

.018 

+ 

.021 

+ 

.024 

166. Huntsville, Ala. 

_ 

.003 

_ 

.002 

+ 

.001 

+ 

.003 

+ 

.005 

4- 

.007 

+ 

.010 

167. Arkansas City, Ark. 

+ 

.003 

+ 

.003 

+ 

.004 

+ 

.005 

+ 

.005 

+ 

.006 

+ 

.007 

168. Memphis, Tenn. 

169. Mammoth Spring, Ark. 

+ 

.001 

+ 

.001 

+ 

.002 

+ 

.002 

+ 

.003 

+ 

.003 

+ 

.004 


.004 


.004 


.003 


.002 


.001 


.000 

+ 

.001 

170. Hopkinsville, Ky. 

4* 

.003 

+ 

.003 

+ 

.005 

+ 

.006 

+ 

.007 

+ 

.008 

+ 

.010 

171. Danville, Ky. 

172. Clifton Forge, Va. 

173. Greenville, Ala. 

+ 

.004 

+ 

.005 

+ 

.008 

+ 

.011 

+ 

.012 

+ 

.015 

+ 

.017 

— 

.014 


.013 


.007 


.003 


.000 

+ 

.005 

+ 

.009 

+ 

.009 

+ 

.011 

+ 

.014 

+ 

.016 

+ 

.018 

+ 

.020 

+ 

.022 


+ 

.003 

+ 

.005 

+ 

.008 

+ 

.011 

+ 

.012 

+ 

.014 

+ 

.017 

— 

.004 

— 

.003 

+ 

.001 

+ 

.005 

+ 

.007 

+ 

.012 

4~ 

.016 

176. Prestonsburg, Ky. 

_ 

.010 

_ 

.009 

_ 

.007 

__ 

.004 

_ 

.003 

_ 

.001 

+ 

.002 

177. Traverse City, Mich. 

+ 

.001 

+ 

.001 

+ 

.001 

+ 

.002 

+ 

.003 

+ 

.003 

+ 

.004 

178. Senev, Mich. 

+ 

.004 

+ 

.004 

+ 

.006 

+ 

.007 

+ 

.007 

+ 

.008 

+ 

.010 

179. Oconto, Wis. 


.000 

— 

.001 


.001 


.001 


.001 


.000 

+ 

.001 

180. Grand Rapids, Wis. 

+ 

.002 

+ 

.003 

+ 

.004 

+ 

.005 

+ 

.006 

+ 

.007 

+ 

.009 

181. Winona, Minn. 

_ 

.008 

_ 

.008 

_ 

.008 

_ 

.006 

_ 

.006 

_ 

.005 

_ 

.004 

182. Baldwin, Wis. 

+ 

.004 

+ 

.005 

+ 

.005 

+ 

.006 

+ 

.006 

+ 

.008 

+ 

.009 

183. Cumberland, Wis. 

184. Cambridge, Minn. 

+ 

.005 

+ 

.005 

+ 

.006 

+ 

.008 

+ 

.008 


.009 

+ 

.011 

+ 

.001 

+ 

.001 

+ 

.002 

+ 

.002 

+ 

.002 

+ 

.003 

+ 

.004 

185. Brainetd, Minn. 

+ 

.001 

+ 

.001 

+ 

.002 

+ 

.003 

+ 

.003 

4- 

.004 

+ 

.005 

186. Aberdeen, S. Dak. 

— 

.004 

_ 

.004 

_ 

.005 

_ 

.005 

_ 

.005 

_ 

.005 

_ 

.005 

187. Faith, S. Dak. 

+ 

.005 

+ 

.005 

+ 

.006 

+ 

.006 


.006 

+ 

.007 

+ 

.008 

188. Marmarth, N. Dak. 

— 

.005 

— 

.005 


.004 


.002 


.001 

.000 

+ 

.003 

189. Towner, N. Dak. 

— 

.003 

— 

.004 

— 

.004 

_ 

.004 

_ 

.005 

_ 

.004 


.003 

190. Crosby, N. Dak. 

+ 

.001 

+ 

.001 

+ 

.001 

+ 

.001 

+ 

.001 

+ 

.001 

+ 

.002 

191. Crookston, Minn. 

_ 

.004 

_ 

.005 

_ 

.006 

_ 

.006 

_ 

.007 

_ 

.006 


.006 

192. Poplar, Mont. 

193. Miles City, Mont. 

— 

.006 

_ 

.007 

_ 

.008 

_ 

.009 

_ 

.009 

_ 

.009 

_ 

.009 

— 

.019 

— 

.020 

_ 

.021 

_ 

.020 

_ 

.020 

_ 

.020 


.018 

194. Huntley, Mont. 

— 

.018 

— 

.020 

_ 

.022 

_ 

.022 

_ 

.022 

_ 

.022 

_ 

.020 

195. Lander, Wyo. 

— 

.037 

— 

.036 

- 

.033 

- 

.028 

- 

.025 

- 

.020 

- 

.013 

196. Faribault, Minn. 

_ 

.001 

_ 

.001 


• 0o0 


.000 

+ 

.001 

+ 

.002 

+ 

.003 

197. St. James, Minn. 

198. Edgemont, S. Dak. 

+ 

.001 

+ 

.001 

+ 

.002 

+ 

.002 

+ 

.002 

+ 

.003 

+ 

.004 

— 

.013 

— 

.014 


.013 


.012 


.011 


.009 


.006 

199. Dawson, Minn. 

— 

.003 

— 

.003 

— 

.003 

_ 

.003 

_ 

.003 

_ 

.003 

_ 

.002 

200. Cokato, Minn. 

+ 

.002 

+ 

.002 

+ 

.002 

+ 

.003 

4- 

.003 

+ 

.003 

+ 

.004 

201. Wasta, S. Dak. 

_ 

.010 

_ 

.011 

_ 

.013 

_ 

.013 


.013 


.012 


.012 

202. Moorcroft, Wyo. 

— 

.001 


.000 

+ 

.002 

+ 

.005 

+ 

.006 

+ 

.009 

+ 

.013 

203. Duluth, Minn. 

— 

.011 

— 

.011 


.011 

.010 


.010 


.009 


.008 

204. Osage, Iowa. 

+ 

.004 

+ 

.004 

+ 

.006 

+ 

.007 

+ 

.007 

+ 

.009 

+ 

.010 

205. Randolph, Nebr. 

+ 

.005 

+ 

.005 

+ 

.005 

+ 

.005 

+ 

.006 

+ 

.006 

+ 

.007 

206. Valentine, Nebr. 


.000 


.000 

+ 

.002 

+ 

.004 

+ 

.005 

+ 

.006 

4- 

.008 

207. Wheeling, W. Va. 

— 

.009 

— 

.008 

.006 


.003 


.002 


.000 

4- 

.003 

208. Leon, Iowa. 

+ 

.005 

+ 

.005 

+ 

.006 

+ 

.007 

+ 

.007 

+ 

.009 

+ 

.010 

209. Laurel, Md. 

210. Harrisburg, Pa. 

+ 

.001 

.004 

+ 

.002 

.003 

4" 

.005 

.000 

+ 

+ 

.007 

.002 

+ 

+ 

.009 

.004 

+ 

+ 

.011 

.007 

+ 

+ 

.014 

.010 

211. Pittsburg, Pa. 

_ 

.005 

_ 

.004 

_ 

.002 


.000 

+ 

.002 

+ 

.004 

4- 

.007 

212. Rockville, Md. 

+ 

.007 

+ 

.008 

+ 

.011 

+ 

.013 

+ 

.015 

+ 

.017 

4- 

.020 

213. Upper Marlboro, Md. 

+ 

.001 

+ 

.002 

+ 

.004 

+ 

.007 

+ 

.009 

+ 

.011 

4- 

.014 

214. Fairfax, Va. 

215. Crisfield, Md. 

+ 

+ 

.006 

.008 

+ 

+ 

.007 

.010 

+ 

+ 

.009 

.014 

+ 

+ 

.011 

.019 

+ 

4" 

.012 

.022 

+ 

+ 

.015 

.025 

+ 

+ 

.018 

.029 

216. Fredericksburg, Va. 

— 

.001 


.000 

+ 

.002 

+ 

.004 

+ 

.006 

+ 

.008 

4- 

.011 

217. Dover, Del. 

218. North Tamarack, Mich. 

+ 

.004 

4" 

+ 

.006 

.018 

+ 

4- 

.009 

.019 

4- 

-f 

.013 

020 

+ 

.014 

+ 

.017 

+ 

.021 

219. Hagerstown, Md. 

— 

.002 

.000 

+ 

.002 

+ 

.006 

+ 

.007 

+ 

.010 

+ 

.014 


The above table needs little comment. In general the effect of topography and compen¬ 
sation increases algebraically with an increase in depth. The largest change from depth of 42.6 
to 184.6 km. is 0.071 dyne at station 114 (Truckee, Cal.). The next greatest change is 0.064, 
at station 43 (Pikes Peak, Colo.). There are some other changes of as much as 0.030 dyne. 
There are a few exceptions to the general rule that the effect of topography and compensation 
increases algebraically with an increase of depth. At station 56 (Seattle, Wash.) the correction 
of —0.009 dyne for depth 42.6 km. decreases algebraically to -0.018 dyne for depth 184.6 km. 
There is no other similar change in the above table greater than 0.005 dyne, except for the 
other Seattle station, No. 53. 




















































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


103 


The greatest changes occur at stations near the coast, especially when the deep water is not 
far distant, and in mountainous regions. Where the topography is comparatively level for some 
distance around the station, the total range in the values for the various depths is small. At sta¬ 
tion 40 (Ellsworth, Ivans.) it is only 0.001 dyne. At station 191 (Crookston, Minn.) the range is 
only 0.003 dyne. At station 144 (Alexandria, La.) the range is 0.008 dyne. The average 
amount of change in the effect of topography and isostatic compensation due to a change in 
depth from 42.6 km. to 184.6 km. is 0.014 dyne. 

GRAVITY ANOMALIES FOR VARIOUS DEPTHS OF COMPENSATION FOR STATIONS IN THE UNITED 

STATES. 

There is given below a table which contains the anomalies of gravity at the 219 stations in 
the United States for various depths. 

Anomalies for various depths of compensation. 


Number of station 

Depth , 42.6 
km . 

Depth , 56.9 
km . 

Depth , 
60.0 km . 

Depth , 85.3 
km . 

Depth , 113.7 
km . 

Depth , 127.9 
km . 

Depth , 156.25 
km . 

Depth , 184.6 
km . 

9-H» 

g— 

(0 c + i2 ) 

!7 

“ 0 c 

9— 

( 00 + 11 ) 

0 — 

( 0 C + 1 O ) 

0 — 0 c 

0 — 

( 0 c + 9 ) 

0 — 0 C 

0 — 

( 0 c + 6 ) 

0 — 0 c 

1 4 

0 — 0 C 

1 4 

0 — 0 c 

0 — 

( 0 .- 1 ) 

1 . 

+ 0.031 

+ 0.019 

+ 0.026 

+ 0.015 

+ 0.015 

+ 0.019 

+ 0.010 

+ 0.013 

+ 0.007 

+ 0.010 

+ 0.005 

+ 0.005 

+ 0.003 

+ 0.001 

+ 0.002 

2 . 

+ .041 

+ .029 

4 

.038 

+ .027 

+ .027 

4 .032 

4 .023 

+ .026 

+ .020 

+ .024 

4 .019 

+ .019 

4 .017 

4 .014 

4 .015 

3 . 

+ .030 

+- .018 

4 - 

.028 

+ .017 

4 .017 

4 .022 

+ .013 

4 .018 

4 .012 

4 .015 

4 .010 

4 .011 

4 .009 

4 .007 

4 .008 

4 . 

+ .017 

+ .005 

+ 

.015 

+ .004 

+ .004 

4 - .011 

+ .002 

4 .008 

+ .002 

4 .006 

4 .001 

4 .003 

4 .001 

.000 

4 .001 


+ .003 

- .009 

+ 

.001 

- .010 

- .010 

- .002 

- .011 

- .005 

- .011 

- .007 

- .012 

- .009 

- .011 

- .012 

- .011 

6 . 

+ .027 

+ .015 

+ 

.027 

+ .016 

+ .017 

+ .026 

+ .017 

4 .024 

4 .018 

4 .024 

4 .019 

4 .022 

+ .020 

4 .021 

+ .022 

7 . 

+ .003 

- .009 

4 - 

.002 

- .009 

- .008 

.000 

- .009 

- .001 

- .007 

- .002 

- .007 

- .004 

- .006 

- .005 

- .004 

8 . 

+ .043 

+ .031 

4 - 

.041 

+ .030 

4 .030 

4 .037 

+ .028 

+ .035 

4 .029 

+ .033 

4 .028 

+ .031 

4 .029 

4 .029 

4 .030 

9 . 

- .013 

- .025 


.012 

- .025 

- .022 

- .012 

- .021 

- .012 

- .018 

- .012 

- .017 

- .013 

- .015 

- .015 

— .014 

10 . 

4 .002 

- .010 

4 - 

.002 

- .009 

- .008 

+ .001 

- .008 

.000 

- .006 

- .001 

- .006 

4 .001 

- .001 

- .003 

- .002 

11 . 

.000 

- .012 


.000 

- .011 

- .010 

- .001 

- .010 

- .002 

- .008 

- .002 

- .007 

- .004 

- .006 

- .005 

- .004 

12 .. 

- .018 

- .030 

_ 

.018 

- .029 

- .028 

- .018 

- .027 

- .019 

- .025 

- .019 

- .024 

- .020 

- .022 

- .021 

— .020 

13 . 

+ .036 

+- .024 

4 

.037 

+ .026 

+ .027 

4 - .038 

4 .029 

4 .038 

+ .032 

- f - . 038 

+ .033 

4 .037 

+ .035 

4 .036 

4 .037 

14 . 

+ .037 

4 .025 

4 - 

.038 

+ .026 

+ .028 

+ .036 

4 .027 

4 .034 

4 .028 

4 .033 

4 .028 

+ .031 

+ .029 

4 .029 

4 .030 


— .009 

- .021 

_ 

.010 

- .021 

- .021 

- .013 

- .022 

- .015 

- .021 

- .016 

- .021 

- .019 

- .021 

- .022 

- .021 

10 . 

4 - .027 

4 .015 

+ 

.027 

+ .016 

4 .017 

4 .026 

+ .017 

4 .023 

4 .017 

+ .021 

4 .016 

+ .019 

+ .017 

4 .016 

4 .017 

17 . 

— .003 

- .015 


. 095 

- .016 

- .016 

- .009 

- .018 

- .013 

- .019 

- .015 

- .020 

- .018 

- .020 

- .021 

- .020 

IS . 

4 .008 

- .004 

4 

.003 

- .008 

- .008 

- .005 

- .014 

- .013 

- .019 

- .017 

- .022 

- .023 

- .025 

- .028 

- .027 

19 . 

— .001 

- .013 


.001 

- .012 

- .011 

- .003 

- .012 

- .005 

- .011 

- .007 

- .012 

- .010 

- .012 

- .013 

- .012 

20 . 

4 .038 

+- .026 

4 - 

.033 

+ .022 

4 .022 

4 .024 

4 .015 

+ .018 

+ .012 

4 .015 

4 .010 

4 .010 

4 .008 

4 .005 

4 .006 

21 . 

4 .049 

+- .037 

4 

.048 

+ .037 

+ .038 

+ .047 

+ .038 

+ .045 

4 .039 

4 .044 

4 .039 

+ .042 

4 .040 

4 .039 

4 .040 

22 . 

+ .051 

4 .039 

4 - 

.050 

+ .039 

4 .040 

+ .049 

4 .040 

+ .047 

+ .041 

4 .045 

4 .040 

+ .043 

4 .041 

+ .040 

4 .041 

23 . 

+ .002 

- .010 

+ 

.002 

- .009 

- .008 

.000 

- .009 

- .003 

- .009 

- .004 

- .009 

- .006 

- .008 

- .009 

- .008 

24 . 

4 .036 

4 .024 

+ 

.035 

+ .024 

4 .025 

+ .033 

4 .024 

+ .030 

4 .024 

+ .028 

4 .023 

4 .025 

+ .023 

4 .022 

4 .023 

25 . 

- .005 

- .017 


.006 

- .017 

- .016 

- .008 

- .017 

- .011 

- .017 

- .013 

- .018 

- .015 

- .017 

- .019 

- .018 

20 . 

4 .039 

+- .027 

4 - 

.038 

+ .027 

+ .027 

4 .035 

+ .026 

+ .032 

4 - .026 

4 .030 

+ .025 

4 .028 

4 .026 

4 .024 

- f - . 025 

27 . 

4 - .037 

+- .025 

+ 

.036 

+ .025 

4 .025 

4 .034 

H ~ . 025 

+ .030 

4 .024 

4 .029 

4 .024 

+ .026 

4 .024 

4 .022 

4 .023 

28 . 

- .001 

- .013 


.004 

- .015 

- .015 

- .007 

- .016 

- .012 

- .018 

- .014 

- .019 

- .018 

- .020 

- .022 

- .021 

29 . 

4 .021 

+- .009 

4 - 

.019 

+ .008 

4 .008 

4 .016 

+ .007 

+ .013 

4 .007 

4 .011 

4 .006 

+ .008 

4 .006 

4 .004 

4 .005 

30 . 

+ .021 

4 - .009 

4 - 

.020 

+ .009 

+ .009 

4 .016 

+ .007 

4 .013 

4 .007 

+ .011 

4 .006 

4 .008 

4 .006 

4 .004 

4 .005 

31 . 

+ .005 

- .007 

4 - 

.004 

- .007 

- .007 

4 .002 

- .007 

.000 

- .006 

- .002 

- .007 

- .003 

- .005 

- .006 

- .005 

32 . 

- .009 

- .021 


.010 

- .021 

- .020 

- .012 

- .021 

- .015 

- .021 

- .016 

- .021 

- .019 

- .021 

- .022 

- .021 

33 . 

4 .007 

- .005 

4 - 

.007 

- .004 

- .003 

+ .007 

- .002 

+ .005 

- .001 

4 .004 

- .001 

+ .003 

4 .001 

4 .002 

4 .003 

34 . 

- .010 

- .022 


.009 

- .020 

- .019 

- .010 

- .019 

- .011 

- .017 

- .012 

- .017 

- .014 

- .016 

- .016 

- .015 

35 . 

.000 

- .012 


.000 

- .011 

- .010 

.000 

- .009 

- .001 

- .007 

- .001 

- .006 

- .002 

- .004 

- .003 

- .002 

30 . 

+ .001 

- .011 

4 

.001 

- .010 

- .009 

+ .002 

- .007 

4 .001 

- .005 

.000 

- .005 

- .001 

- .003 

- .003 

- .002 

37 . 

+ .005 

- .007 

+ 

.005 

- .006 

- .005 

+ . 004 

- .005 

4 .003 

- .003 

4 .002 

- .003 

4 .001 

- .001 

- .001 

.000 

38 . 

+ .002 

- .010 

4 - 

.003 

- .008 

- .007 

+ .003 

- .006 

+ .003 

- .003 

4 .003 

- .002 

+ .002 

.000 

4 .002 

4 .003 

39 

- .009 

- .021 


.008 

- .019 

- .018 

- .007 

- .016 

- .008 

- .014 

- .008 

- .013 

- .008 

- .010 

- .009 

- .008 

40 . 

+ .021 

4 .009 

4 - 

.022 

+ .011 

+ .012 

4 .022 

4 .013 

+ .022 

4 .016 

4 .022 

4 .017 

4 .022 

4 .020 

+ .021 

4 .022 

41 . 

+ .003 

- .009 

+ 

.002 

- .009 

- .009 

- .001 

- .010 

- .004 

- .010 

- .005 

- .010 

- .007 

- .009 

- .010 

- .009 

42 . 

+ .018 

+ .006 

4 

.014 

+ .003 

+ .003 

+ .008 

- .001 

+ .001 

- .005 

- .002 

- .007 

- .008 

- .010 

- .016 

- .015 

43 . 

+ .069 

4 - .057 

4 - 

.057 

4 .046 

+ .045 

4 .041 

+ .032 

4 .029 

+ .023 

4 .024 

4 .019 

4 .015 

4 .013 

4 .005 

4 .006 

44 

- .008 

- .020 


.006 

- .017 

- .016 

- .005 

- .014 

- .008 

- .014 

- .010 

- .015 

— .014 

- .016 

- .019 

- .018 

45 . 

+ .051 

+ .039 

+ 

.048 

4 .037 

+ .037 

+ .039 

+ .030 

+ .028 

4 .022 

~r • 023 

4 .018 

+ .014 

+ .012 

+ .003 

4 .004 

46 . 

+ .031 

4 - .019 

+ 

.034 

+ .023 

+ .024 

+ .035 

+ .026 

+ .032 

+ .026 

4 .030 

+ .025 

4 .027 

+ .025 

4 . u 21 

+ .022 

47 

- .020 

- .032 


.016 

- .027 

- .026 

- .013 

- .022 

- .013 

- .019 

- .013 

- .018 

- .015 

- .017 

- .018 

- .017 

48 

+ .038 

4 - .026 

+ 

.032 

+ .021 

4 .021 

+ .022 

+ .013 

+ .012 

+ .006 

+ .008 

4 .003 

4 .001 

- .001 

- .006 

- .005 

49 . 

+ .021 

4 - .009 

4- 

.021 

4 .010 

+ .011 

+ .021 

+ .012 

4 - .018 

+ .012 

4 .017 

+ .012 

4 .014 

4 .012 

4 .009 

4 .010 

50 . 

+ .035 

+ .023 

4 - 

.029 

4 .018 

+ .017 

+ .017 

+ .008 

+ .006 

.000 

+ .001 

— .004 

- .007 

- .009 

— .016 

- .015 

51 . 

+ .055 

4 - .043 

+ 

.049 

+ .038 

- 4 - . 038 

4 .039 

+ .030 

4 .029 

4 .023 

4 .024 

+ .019 

4 .016 

4 .014 

+ .008 

4 .009 

52 

+ .031 

4 - .019 

4- 

.026 

+ .015 

+ .015 

+ .017 

4 - .008 

+ .007 

4 .001 

+ .002 

- .003 

— .005 

— .007 

- .014 

- .013 

53 

- .093 

- .105 


.090 

- .101 

- .100 

- .086 

- .095 

- .085 

- .091 

- .084 

- .089 

- .084 

— .086 

— . 08 o 

— .084 


+ .006 

- .006 

+ 

.001 

- .010 

- .010 

- .008 

- .017 

- .015 

- .021 

- .018 

- .023 

- .023 

- .025 

- .028 

- .027 

55. 

4 .033 

+ .021 

4- 

.025 

+ .014 

4 .013 

4 .013 

4 .004 

+ .005 

- .001 

4 .001 

- .004 

- .005 

- .007 

— .010 

— .009 

56 . 

- .094 

- .106 


.090 

- . 101 

- . 100 

- .086 

- .095 

- .085 

- .091 

- .085 

- .090 

- .085 

- .087 

- .085 

- . 0 S 4 

57 


4 - .042 

+ 

.052 

4 .041 

+ .041 

+ .049 

+ .040 

4 .046 

+ .040 

4 .044 

+ .039 

4 .042 

• 040 

4 .040 

4 .041 

58 

4 - .035 

4 .023 

4- 

.034 

+ .023 

4 .023 

4 .032 

4 .023 

+ .031 

+ .025 

4 .030 

+ .025 

4 .029 

4 .027 

H ~ • 021 

"k • 02 s 

59 

+ .024 

+ .012 

4- 

.025 

+ .014 

+ .015 

+ .026 

+ .017 

+ .027 

+ .021 

4 .027 

+ .022 

4 .027 

4 .025 

+ .027 

4 .028 

00 . 

+ .007 

- .005 

4- 

.007 

- .004 

- .003 

+ .008 

- .001 

+ .009 

+ .003 

+ .009 

4 .004 

+ .009 

+ .007 

+ .009 

+ • 010 










































































































104 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40 


Anomalies for various depths of compensation —Continued. 


Number of station 

Depth, 42.6 
km. 

Depth, 56.9 
km. 

Depth, 
60.0 km. 

Depth, 85.3 
km. 

Depth, 113.7 
km. 

Depth, 127.9 
km. 

Depth, 156.25 
km. 

Depth, 184.6 
km. 

g—g o 

9— v 

(?c+12) 

9 — g<s 

9— , 
(0.+11) 

g — 

(00+10) 

9 — 9c 

1 + 

9 — 9° 

(0c4-6) 

9 — 9c 

9— 

(0o4-5) 

9 — 9c 

9— 

(<7o4-2) 

9 — 9c 

9— 

t9c— 1) 

61. 

-0.015 

-0.027 

-0.017 

-0.028 

-0.028 

-0.019 

-0.028 

-0.021 

-0.027 

-0.022 

-0.027 

-0.025 

-0.027 

-0. 027 

-0.026 

62. 

+ .049 

+ .037 

4- .046 

4- .035 

+ .035 

4- .042 

4- .033 

4- .039 

4- .033 

4- .037 

4- .032 

4- .034 

4- .032 

4- .031 

4- .032 

63. 

+ .021 

+ .009 

4- .020 

+ .009 

+ .010 

+ .018 

+ .009 

4- .015 

4- .009 

4- .014 

4- .009 

4- .011 

4- .. 009 

4- .007 

4- .008 

64.. 

- .024 

- .036 
+ .003 

- .029 
+ .016 

— .040 

— .040 

- .036 

- .045 
+ .008 

- .042 
4- .017 

- .048 
4- .011 

— .044 

— .049 

- .048 

— .050 

- .053 

— .052 

65. 

+ .015 

+ .005 

+ .006 

+ .017 

4- .017 

4- .012 

4- .016 

4- .014 

4- .015 

4- .016 

66... 

- .037 

- .049 
+ .004 

- .038 
+ .010 

- .049 

— .049 

— .040 

- .049 

- .1,06 

- .042 

- .005 

- .048 

- .011 

- .044 

- .049 

- .014 

- .047 

— .049 

- .051 

- .050 

- .023 

67. 

4- .0161 

- .001 

- .001 

+ .003 

- .009 

- .016 

- .018 

- .024 

68. 

+ .027 

+ .015 

+ .023 

+ .012 

+ .012 

+ .016 

+ .007 

4- .009 

4- .003 

4- .006 

4- .001 

4- .001 

- .001 

- .007 

- .006 

69. 

+ .012 

.000 

+ .010 

- .001 

- .001 

+ .004 

- .005 

- .002 

- .OOS 

- .005 

- .010 

- .010 

- .012 

- .018 

- .017 

70. 

+ .015 

+ .003 

4- .010 

- .001 

- .001 

+ .003 

- .006 

- .005 

- .011 

- .009 

- .014 

— .015 

- .017 

- .023 

- .022 

71. 

4- .032 

+ .020 

+ .027 

+ .016 

+ .016 

+ .019 

4- .010 

4- .011 

4- .005 

4- .007 

4- .002 

4- .001 

- .001 

- .007 

- .006 

72. 

+ .044 

+ .032 

4- .044 

+ .033 

+ .034 

+ .042 

4- .033 

4- .040 

4- .034 

4- .039 

4- .034 

4- .037 

4- .035 

4- .035 

4- .036 

73. 

4- .014 

+ .002 

+ .014 

+ .003 

+ .004 

+ .013 

4- .004 

4- .013 

4- .007 

4- .012 

4- .007 

4- .011 

4- .009 

4- .010 

4- .011 

74. 

+ .066 

+ .054 

+ .067 

+ .056 

+ .057 

+ .067 

4- .058 

4- .067 

4- .061 

4- .067 

4- .062 

4- .067 

4- .065 

4- .066 

4- .067 

75. 

4- .079 

+ .067 

+ .073 

4- .062 

+ .062 

+ .066 

4- .057 

4- .060 

4- . 054 

4- .057 

4- .052 

4- .053 

4- .051 

4- .049 

4- -050 

76. 

+ .010 

- .002 

+ .010 

- .001 

.000 

4- .011 

4- .002 

4- .010 

4- .004 

4- .010 

4- .005 

4- .010 

4- .008 

4- .009 

4- .010 

77. 

+ .032 

+ .020 

+ .034 

+ .023 

+ .024 

4- .035 

4- .026 

4- .037 

4- .031 

4- .037 

4- .032 

4- .038 

4- .036 

4- .037 

4- .038 

78. 

+ .008 

- .004 

+ .010 

- .001 

.000 

+ .011 

4- .002 

4- .010 

4- .004 

4- .010 

4- .005 

4- .008 

4- .006 

4- .006 

4- .007 

79. 

+ .009 

- .003 

+ .012 

+ .001 

+ .002 

+ .015 

4- .006 

4- .016 

4- .010 

4- .016 

4- .011 

4- .016 

4- .014 

4- .014 

4- .015 

80. 

+ .002 

- .010 

+ .001 

- .010 

- .010 

- .002 

- .011 

- .005 

- .011 

- .005 

- .010 

- .008 

- .010 

- .010 

- .009 

81. 

+ .028 

4- .016 

+ .021 

+ .010 

+ .009 

4- .009 

.000 

- .002 

- .008 

- .007 

- .012 

- .016 

- .018 

- .025 

- .024 

82. 

+ .034 

+ .022 

+ .031 

+ .020 

+ .020 

+ .027 

4- .018 

4- .021 

4- .015 

4- .019 

4- .014 

4- .014 

4- .012 

4- .007 

4- .008 

83. 

+ .004 

- .008 

+ .005 

- .006 

- .005 

+ .004 

- .005 

4- .002 

- .004 

4- .002 

- .003 

.000 

- .002 

- .002 

- .001 

84. 

4- .049 

+ .037 

+ .049 

+ .038 

+ .039 

4- .047 

4- .038 

4- .045 

4- .039 

4- .044 

4- .039 

4- .042 

4- .040 

4- .039 

4- .040 

85. 

+ .007 

- .005 

+ .008 

- .003 

- .002 

+ .009 

.000 

4- .009 

4- .003 

4- .008 

4- .003 

4- .007 

4- .005 

4- .005 

4- .006 

86. 

+ .032 

+ .020 

4- .027 

+ .016 

+ .016 

+ .020 

4- .011 

4- .014 

4- .008 

4- .012 

4- .007 

4- .007 

4- .005 

4- .003 

4- .004 

87. 

+ .032 

+ .020 

+ .031 

+ .020 

+ .021 

+ .030 

4- .021 

4- .029 

4- .023 

4- .028 

4- .023 

4- .026 

4- .024 

4- .024 

4- .025 

88. 

- .004 

- .016 

- .003 

- .014 

- .013 

- .002 

- .011 

- .002 

- .008 

- .003 

- .008 

- .003 

- .005 

- .004 

- .003 

89. 

- .008 

- .020 

- .009 

- .020 

- .019 

- .010 

- .019 

- .012 

- .018 

- .012 

- .017 

- .014 

- .016 

- .015 

.014 

90. 

- .025 

- .037 

- .028 

- .039 

- .039 

- .034 

- .043 

- .040 

- .046 

- .013 

- .048 

- .047 

- .049 

- .052 

- .051 

91. 

4- .049 

+ .037 

+ .049 

+ .038 

+ .038 

+ .047 

4- .038 

4- .044 

4- .038 

4- .042 

4- .037 

4- .039 

4- .037 

4- .036 

4- .037 

92. 

4- .028 

+ .016 

4- .026 

+ .015 

+ .015 

+ .022 

4- .013 

4- .018 

4- .012 

4- .016 

4- .011 

4- .012 

4- .010 

4- .009 

4- .010 

93. 

- .029 

- .041 

- .031 

- .042 

- .042 

- .034 

- .043 

- .036 

- .042 

- .037 

- .042 

- .040 

- .042 

- .043 

- .042 

94. 

- .007 

- .019 

- .007 

- .018 

- .017 

- .008 

- .017 

- .009 

- .015 

- .010 

- .015 

- .011 

- .013 

- .013 

- .012 

95. 

+ .007 

- .005 

+ .008 

- .003 

- .002 

+ .009 

.000 

4- .009 

4- .003 

4- .009 

4- .004 

4- .009 

4- .007 

4- .008 

4- .009 

96. 

- .040 

- .052 

- .041 

- .052 

- .051 

- .042 

- .051 

- .044 

- .050 

- .044 

- .049 

- .046 

- .048 

- .047 

- .046 

97. 

- .003 

- .015 

- . 003 

- .014 

- .013 

- .003 

- .012 

- .004 

- .010 

- .004 

- .009 

- .005 

- .007 

- .006 

- .005 

98. 

4- .049 

4- .037 

+ .045 

4- .034 

+ .034 

+ .037 

4- .028 

4- .029 

4- .023 

4- .026 

4- .021 

4- .020 

4- .018 

4- .014 

4- .015 

99. 

.000 

- .012 

- .002 

- .013 

- .013 

- .005 

- .014 

- .008 

- .014 

- .010 

- .015 

- .013 

- .015 

- .018 

- .017 

100. 

- .007 

- .019 

- .006 

- .017 

- .016 

- .007 

- .016 

- .009 

- .015 

- .010 

- .015 

- .012 

- .014 

- .015 

- .014 

101. 

4- .058 

+ .046 

+ .056 

+ .045 

+ .045 

+ .052 

4- .043 

4- .048 

4- .042 

4- .046 

4- .041 

4- .043 

4- .041 

4- .039 

4- .040 

102. 

+ .040 

+ .028 

+ .033 

4- .022 

+ .021 

4- .021 

4- .012 

4- .012 

4- .006 

4- .008 

4- .003 

4- .001 

- .001 

- .005 

- .004 

103. 

+ .006 

- .006 

- .001 

- .012 

- .012 

- .012 

- .021 

- .021 

- .027 

- .024 

- .029 

- .031 

- .033 

- .037 

- .036 

104. 

- .015 

- .027 

- .014 

- .025 

- .024 

- .015 

- .024 

- .016 

- .022 

- .017 

- .022 

- .019 

- .021 

- .022 

- .021 

105. 

- .005 

- .017 

- .006 

- .017 

- .017 

- .009 

- .018 

- .013 

- .019 

- .015 

- .020 

- .018 

- .020 

- .022 

- .021 

106. 

- .004 

- .016 

- .004 

- .015 

- .014 

- .004 

- .013 

- .005 

- .011 

- .006 

- .011 

- .007 

- .009 

- .009 

- .008 

107. 

+ .039 

+ .027 

+ .037 

4- .026 

4- .026 

+ .034 

4- .025 

4- .032 

4- .026 

4- .031 

4- .020 

4- .029 

4- .027 

4- .027 

4- .028 

108. 

+ .001 

- .011 

+ .002 

- .009 

- .008 

+ .002 

- .007 

4- .002 

- .004 

4- .002 

- .003 

4- .002 

.000 

4- .001 

4- .002 

109. 

4- .044 

+ .032 

+ .045 

+ .034 

4- .035 

+ .043 

4- .034 

4- .040 

4- .034 

4- .038 

4- .033 

4- .034 

4- .032 

4- .030 

4- .031 

110. 

+ .008 

- .004 

+ .005 

- .006 

- .006 

- .001 

- .010 

- .007 

- .013 

- .009 

- .014 

- .014 

- .016 

- .020 

- .019 

Ill. 

- .004 

- .016 

- .008 

- .019 

- .019 

- .014 

- .023 

- .020 

- .026 

- .022 

- .027 

- .026 

- .028 

- .030 

- .029 

112. 

+ .037 

+ .025 

+ .039 

+ . 02S 

+ .029 

+ .041 

4- .032 

4- .041 

4- .035 

4- .040 

4- .035 

4- .040 

4- .038 

4- .038 

4- .039 

113. 

- .021 

- .033 

- .020 

- .031 

- .030 

- .019 

- .028 

- .019 

- .025 

- .020 

- .025 

- .021 

- .023 

- .022 

- .021 

114. 

+ .023 

+ .011 

+ .012 

+ .001 

.000 

- .006 

- .015 

- .020 

- .026 

- .027 

- .032 

- .037 

- .039 

- .048 

- .047 

115. 

+ .003 

- .009 

+ .004 

- .007 

- .006 

+ .002 

- .007 

- .001 

- .007 

- .003 

- .008 

- .007 

- .009 

- .013 

- .012 

116. 

+ .014 

+ .002 

+ .008 

- .003 

- .003 

- .003 

- .012 

- .013 

- .019 

- .018 

- .023 

- .026 

- .028 

- .034 

- .033 

117. 

+ .043 

4- .031 

+ .045 

+ .034 

+ .035 

+ .046 

4- .037 

4- .044 

4- .038 

4- .043 

4- .038 

4- .041 

4- .039 

4- .038 

4- .039 

118. 

4- .018 

+ .006 

+ .019 

+ .008 

+ .009 

+ .021 

4- .012 

4- .022 

4- .016 

4- .022 

4- .017 

4- .023 

4- .021 

4- . 023 

4- .024 

119. 

+ .023 

+ .011 

+ .023 

+ .012 

+ .013 

+ .024 

4- .015 

4- .023 

4- .017 

4- .023 

4- .018 

4- .023 

4- .021 

4- .021 

4- .022 

120. 

4- .002 

- .010 

+ .002 

- .009 

- .008 

.000 

- .009 

.000 

- .006 

- .001 

- .006 

- .001 

- .003 

- .002 

- .001 

121. 

+ .012 

.000 

+ .012 

+ .001 

4- .002 

+ .011 

4- .002 

4- .010 

4- .004 

4- .009 

4- .004 

4- .008 

4- .006 

4- .007 

4- .008 

122. 

4- .022 

+ .010 

+ .022 

4- .011 

+ .012 

+ .020 

4- .011 

4- .019 

4- .013 

4- .018 

4- .013 

4- .016 

4- .014 

4- .015 

4- .016 

123. 

- .031 

- .043 

- .031 

- .042 

- .041 

- .032 

- .041 

- .035 

- .041 

- .037 

- .042 

- .040 

- .042 

- .043 

- .042 

124. 

- .014 

- .026 

- .016 

- .027 

- .027 

- .020 

- .029 

- .025 

- .031 

- .02? 

- .032 

- .031 

- .033 

- .035 

— .034 

125. 

- .004 

- .016 

- .007 

- .018 

- .018 

- .011 

- .020 

- .015 

- .021 

- .018 

- .023 

- .021 

- .023 

- .025 

- .024 

126. 

- .002 

- .014 

- .005 

- .016 

- .016 

- .010 

- .019 

- .014 

- .020 

- .016 

- .021 

- .020 

- .022 

- .024 

- .023 

127. 

+ .008 

- .004 

+ .004 

- .007 

- .007 

- .001 

- .010 

- .006 

- .012 

- .009 

- .014 

- .013 

- .015 

- .018 

- .017 

128. 

.000 

- .012 

- .002 

- .013 

- .013 

- .004 

- .013 

- .007 

- .013 

- .008 

- .013 

- .010 

— .012 

- .013 

- .012 

129. 

+ .003 

- .009 

.000 

- .011 

- .011 

- .005 

- .014 

- .010 

- .016 

- .012 

- .017 

- .016 

- .018 

- .020 

- .019 

130. 

- .026 

- .038 

- .027 

- .038 

- .037 

- .028 

- .037 

- .031 

- .037 

- .032 

- .037 

- .035 

- .037 

- .039 

- .038 

131. 

- .009 

- .021 

- .010 

- .021 

- .021 

- .013 

- .022 

- .016 

- .022 

- .018 

- .023 

- .022 

- .024 

- .026 

- .025 

132 . 

133 . 

- .014 

- .026 
- .023 

- .014 

- .013 

- .025 

- .024 

- .024 

- .024 

- .015 

- .018 

- .024 

- .027 

- .017 

- .022 

- .023 

- .028 

- .018 
- .024 

- .023 

- .029 

- .020 
- .028 

- .022 
- .030 

- .021 
- .032 

- .020 
- .031 

134. 

- .016 

- .028 

- .017 

- .028 

- .027 

- .018 

- .027 

- .019 

- .025 

- .020 

- .025 

- .021 

- .023 

- .023 

- .022 

135. 

- .012 

- .024 

- .013 

- .024 

- .023 

- .014 

- .023 

- .016 

- .022 

- .017 

- .022 

- .019 

- .021 

- .022 

- .021 

136. 

- .001 

- .013 

- .001 

- .012 

- .011 

- .002 

- .011 

- .004 

- .010 

- .005 

- .010 

- .007 

- .009 

- .009 

- .008 

137. 

+ .013 

+ .001 

+ .012 

+ .001 

+ .002 

+ .010 

4- .001 

4- .009 

4- .003 

4- .008 

4- .003 

4- .006 

4- .004 

4- .005 

4- .006 

138. 

- .007 

- .019 

- .007 

- .018 

- .017 

- .007 

- .016 

- .008 

- .014 

- .008 

- .013 

- .009 

- .011 

- .009 

- .008 

139. 

+ .024 

4- .012 

+ .023 

+ .012 

+ .012 

+ .021 

4- .012 

4- .019 

4- .013 

4- -019 

4- .014 

4- .017 

4- .015 

4- .015 

4- .016 

140. 

1+ .027 

4- .015 

+ .026 

+ .015 

+ .016 

4- .025 

+ .016 

4- .024 

4- .018 

4- .024 

4- .019 

4- .022 

4- .020 

4- .021 

4- .022 






































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


105 


Anomalies for various depths of compensation —•Continued. 



Depth, 42.6 
km. 

Depth, 56.9 
km. 

Depth, 
>0.0 km. 

Depth, 85.3 
km. 

Depth, 113.7 
km. 

Depth, 127.9 
km. 

Depth, 156.25 
km. 

Depth, 184.6 
km. 


9~9c 

9— v 

f7o+12) 

9 — 9c ( 

9— 

!7c+ll) 

9— 

!</o4-10) 

9-9 o 

1 + 

9—9c 

9— 

(?o4-6) 

9—9c 

1 + 

9—9c 

1 + 

9 — 9c 

9~ 

(9 c —1) 

141. 

-0.009 

-0.021 

-0.008 

-0.019 

-0.018 

-0.007 

-0.016 

-0.008 

-0.014 

-0.008 

-0.013 

-0.009 

-0.011 

-0.010 

-0.009 

142. 

4- .019 

+- .007 

4- .019 

4- .008 

4- .009 

4- .020 

4- .011 

4- .019 

4- .013 

4- .019 

4- .014 

4- .018 

4- .016 

4- .018 

4- .019 

143. 

4- .028 

4- .016 

4- .028 

4- .017 

4- .018 

4- .027 

4- .018 

4- .026 

4- .020 

t- .025 

4- .020 

4- .024 

4- .022 

4- .022 

4- .023 

144. 

4- .006 

- .006 

4- .005 

- .006 

- .005 

4- .003 

- .006 

4- .002 

- . 004 

4- .001 

- .004 

- .001 

- .003 

- .002 

- .001 

145. 

+ .028 

4- .016 

4- .027 

4- .016 

4- .016 

4- .024 

■f .015 

4- .022 

4- .016 

■f .020 

4- .015 

4- .018 

4- .016 

4- .016 

4- .017 

146. 

4- .017 

-f .005 

4- .016 

4- .005 

4- .005 

4- .014 

4- .005 

4- .011 

4- .005 

4- .010 

4- .005 

4- .007 

4- .005 

4- .004 

4- .005 

147. 

+ .029 

4- .017 

4- .027 

4- .016 

4- .016 

4- .024 

4- .015 

4- .021 

4- .015 

+ .019 

4- .014 

4- .016 

4- .014 

+ .013 

4- .014 

148. 

+ .001 

- .011 

- .001 

- .012 

- .012 

- .006 

- .015 

- .010 

- .016 

- .012 

- .017 

- .016 

- .018 

- .020 

- .019 

149. 

- .010 

- .022 

- .013 

- .024 

- .024 

- .018 

- .027 

- .023 

- .029 

- .026 

- .031 

- .030 

- .032 

- .035 

- .034 

150. 

4- .017 

4- .005 

4- .016 

4- .005 

4- -005 

4- .013 

4- .004 

4- .010 

4- .004 

4- .009 

4- .004 

4- .006 

4- .004 

4- .002 

4- .003 

151. 

+ .042 

4- .030 

4- .040 

4- .029 

4- -029 

4- .037 

4- .028 

4- .033 

+ .027 

4- .032 

4- -027 

4- .028 

4- .026 

4- .024 

4- .025 

152. 

+ .025 

4- .013 

4- .020 

+ .009 

4- .009 

4- .011 

4- .002 

+ .003 

- .003 

.000 

- .005 

- .006 

- .008 

- .012 

- .011 

153. 

- .007 

- .019 

- .009 

- .020 

- .020 

- .012 

- .021 

- .015 

- .021 

- .016 

- .021 

- .019 

- .021 

- .022 

- .021 

154 


- .033 

- .019 

- .023 

- .008 

- .034 

- .019 

- .034 

- .019 

- .027 

- .010 

- .036 

- .019 

- .030 

- .013 

- .036 

- .019 

- .032 

- .014 

- .037 

- .019 

- .036 

- .017 

- .038 

- .019 

- .039 

- .020 

- .038 

- .019 

155. 

- .007 

156. 

+ .007 

- .005 

4- .004 

- .007 

- .007 

- .002 

- .011 

- .007 

- .013 

- .009 

- .014 

- .014 

- .016 

- .019 

- .018 

157. 

- .012 

- .024 

- .015 

- .026 

- .026 

- .023 

- .032 

- . 02S 

- .034 

- .031 

- .036 

- .036 

- .038 

- .041 

- .040 

158. 

4- .004 

- .008 

4- .001 

- .010 

- .010 

- .004 

- .013 

- .009 

- .015 

- .011 

- .016 

- .016 

- .018 

- .020 

- .019 

159. 

4- -021 

4- .009 

4- .018 

4- .007 

4- .007 

4- .012 

4- -003 

4- .007 

4- .001 

4- .005 

• 000 

.000 

- .002 

- .004 

- .003 

160. 

+ .006 

- .006 

4- .003 

- .008 

- .008 

- .001 

- .010 

- .006 

- .012 

- .008 

- .013 

- .012 

- .014 

- .016 

- .015 

161. 

- .003 

- .015 

- .005 

- .016 

- .016 

- .009 

- .018 

- .013 

- .019 

- .015 

- .020 

- .019 

- .021 

- .022 

- .021 

162. 

4- .033 

4- .021 

4- .032 

4- .021 

4- .021 

4- .030 

4- .021 

4- -027 

4- -021 

4- .026 

4- .021 

4- .024 

4- .022 

4- .021 

4- .022 

163. 

+ .017 

4- .005 

4- .016 

4- .005 

4- .005 

4- .013 

4- .004 

4- -010 

4- .004 

4- .009 

4- .004 

4- .006 

4- .004 

4- .003 

4- -004 

164. 

4- .003 

- .009 

4- .001 

- .010 

- .010 

- .002 

- .011 

- .006 

- .012 

- .007 

- .012 

- .010 

- .012 

- .012 

- .011 

165. 

- .007 

- .019 

- .009 

- .020 

- .020 

- .013 

- .022 

- .017 

- .023 

- .018 

- .023 

- .021 

- .023 

- .024 

- .023 

166. 

- .009 

- .021 

- .010 

- .021 

- .021 

- .013 

- .022 

- .015 

- .021 

- .017 

- .022 

- .019 

- .021 

- .022 

- .021 

167. 

- .002 

- .014 

- .002 

- .013 

- .012 

- .003 

- .012 

- .004 

- .010 

- .004 

- .009 

- .005 

- .007 

- .006 

- .005 

168. 

4- .022 

4- -010 

4- .022 

4- .011 

4- .012 

4- .021 

4- .012 

4- .021 

4- -015 

4- .020 

4- .015 

4- .020 

4- -018 

4- .019 

4- .020 

169. 

4- .023 

4- -Oil 

4- -023 

4- .012 

4- .013 

4- .022 

4- .013 

4- .021 

4- .015 

4- .020 

4- .015 

4- .019 

4- .017 

4- .018 

4- .019 

170. 

+ -017 

4- .005 

4- .017 

4- .006 

4- -007 

4- .015 

4- .006 

4- .014 

4- .008 

4- .013 

4- .008 

4- .012 

4- .010 

4- -010 

4- .011 

171. 

- .014 

- .026 

- .015 

- .026 

- .026 

- .018 

- .027 

- .021 

- .027 

- .022 

- .027 

- .025 

- .027 

- .027 

- .026 

172. 

- .015 

- .027 

- .016 

- .027 

- .027 

- .022 

- .031 

- .026 

- .032 

- .029 

- .034 

- .034 

- .036 

- .038 

- .037 

173. 

4- .004 

- .008 

4- -002 

- .009 

- .009 

- .001 

- .010 

- .003 

- .009 

- .005 

- .010 

- .007 

- .009 

- .009 

- .008 

174. 

- .017 

- .029 

- .019 

- .030 

- .030 

- .022 

- .031 

- .025 

- .031 

- .026 

- .031 

- .028 

- .030 

- .031 

- .030 

175. 

- .007 

- .019 

- .008 

- .019 

- .019 

- .012 

- .021 

- .016 

- .022 

- .018 

- .023 

- .023 

- .025 

- .027 

- .026 

176. 

- .010 

- .022 

- .011 

- .022 

- .022 

- .013 

- .022 

- .016 

- .022 

- .017 

- .022 

- .019 

- .021 

- .022 

- .021 

177. 

+ .010 

- .002 

4- .010 

- .001 

.000 

4- .010 

4- .001 

4- .009 

4- .003 

4- .008 

4- .003 

4- .008 

4- .006 

4- .007 

4- .008 

178. 

4- .012 

.000 

4- .012 

4- .001 

4- .002 

4- .010 

4- .001 

4- .009 

4- .003 

4- .009 

4- -004 

4- .008 

4- .006 

4- .006 

4- .007 

179. 

- .018 

- .030 

- .017 

- .028 

- .027 

- .017 

- .026 

- .017 

- .023 

- .017 

- .022 

- .018 

- .020 

- .019 

- .018 

180. 

- .031 

- .043 

- .032 

- .043 

- .042 

- .033 

- .042 

- .034 

- .040 

- .035 

- .040 

- .036 

- .038 

- .038 

- .037 

181. 

+ .025 

4- .013 

4- .025 

4- .014 

4- .015 

4- .025 

4- .016 

4- .023 

4- .017 

4- .023 

4- .018 

4- .022 

4- .020 

4- .021 

4- .022 

182. 

- .040 

- .052 

- .041 

- .052 

- .051 

- .041 

- .050 

- .042 

- .048 

- .042 

- .047 

- .044 

- .046 

- .045 

- .044 

183. 

- .038 

- .050 

- .038 

- .049 

- .048 

- .039 

- .048 

- .041 

- .047 

- .041 

- .046 

- .042 

- .044 

- .044 

- .043 

184. 

— .018 

- .030 

- .018 

- .029 

- .028 

- .019 

- .028 

- .019 

- .025 

- .019 

- .024 

- .020 

- .022 

- .021 

- .020 

185. 

4- .022 

4- .010 

4- .022 

4- .011 

4- .012 

4- .021 

4- .012 

4- .020 

4- .014 

4- .020 

4- .015 

4- .019 

4- .017 

4- .018 

4- .019 

186. 

+ .019 

4- .007 

4- .019 

4- .008 

4- .009 

4- -020 

4- .011 

4- .020 

4- .014 

4- .020 

4- .015 

4- .020 

4- -018 

4- .020 

4- .021 

187. 

4- .024 

4- .012 

4- -024 

4- .013 

4- .014 

4- .023 

4- .014 

4- .023 

4- .017 

4- .023 

4- -018 

4- .022 

4- .020 

4- .021 

4- .022 

188. 

+ -046 

4- .034 

4- .046 

4- .035 

4- .036 

4- .045 

4- .036 

4- -043 

4- .037 

4- .042 

4- -037 

4- .041 

4- .039 

4- -038 

4- .039 

189. 

+ -039 

4- .027 

4- .040 

4- .029 

4- .030 

4- .040 

4- .031 

4- .040 

4- .034 

4- .041 

4- -036 

4- -040 

4- -038 

4- -039 

4- .040 

190. 

4- .025 

4- -013 

4- .025 

4- .014 

4- -015 

4- .025 

4- .016 

4- -025 

4- .019 

4- .025 

4- -020 

4- .025 

4- -023 

4- -024 

4- .025 

191 . 

+ .017 

4- -005 

4- -018 

4- .007 

4- -008 

4- .019 

4- .010 

4- .019 

4- .013 

4- .020 

4- -015 

4- .019 

4- .017 

4- .019 

4- .020 

192. 

+ .024 

4- .012 

4- .025 

4- .014 

4- .015 

4- -026 

4- .017 

4- .027 

4- -021 

4- .027 

4- -022 

4- .027 

4- .025 

4- .027 

4- .028 

193. 

+ 037 

4- .025 

4- .038 

4- .027 

4- -028 

4- .039 

4- .030 

4- .038 

4- -032 

4- .038 

4- -033 

4- .038 

4- -036 

4- .036 

4- .037 

194 . 

4- .015 

4- .003 

4- .017 

4- -006 

4- .007 

4- .019 

4- .010 

4- .019 

4- -013 

4- -019 

4- .014 

4- .019 

4- -017 

4- .017 

4- .018 

195. 

+ .036 

4- .024 

4- -035 

4- -024 

4- -024 

4- -032 

4- .023 

4- .027 

4- .021 

4- .024 

4- .019 

4- -019 

4- -017 

4- .012 

4- .013 

196 . 

+ .045 

4- .033 

4- -045 

4- .034 

4- -035 

4- .044 

4- .035 

4- .044 

4- -038 

4- .043 

4- .038 

4- -042 

4- .040 

4- -041 

4- .042 

197 . 

+ .015 

4- .003 

4- .015 

4- -004 

4- .005 

4- .014 

4- .005 

4- -014 

4- -008 

4- -014 

4- .009 

4- -013 

4- .011 

4- -012 

4- .013 

198 . 

4- .063 

4- .051 

4- .064 

4- .053 

4- .054 

4- .063 

4- .054 

4- .062 

4- -056 

4- .061 

4- -056 

4- -059 

4- -057 

•+• . 056 

4- .057 

199 

+ .025 

4- .013 

4- .025 

4- -014 

4- 015 

4- .025 

4- -016 

4- -025 

4- -019 

4- .025 

4- -020 

4- -025 

4- -023 

4- .024 

4- .025 

200. 

+ .015 

4- .003 

4- .015 

4- -004 

4- -005 

4- .015 

4- .006 

4- -014 

4- -008 

4- -014 

4- .009 

4- -014 

4- -012 

4- -013 

4- .014 

201 

4- .035 

4- .023 

4- -036 

4- -025 

4- -026 

4- .038 

4- .029 

4- -038 

4- -032 

4- .038 

4- -033 

4- -037 

4- .035 

4- .037 

4- .038 

202 

+ .035 

4- .023 

4- -034 

4- 023 

4- .024 

4- .032 

4- .023 

4- -029 

4- .023 

4- -028 

4- .023 

4- -025 

4- .023 

4- -021 

4- .022 

203 

+ .059 

4- .047 

4- -059 

4- -048 

4- .049 

4- .059 

4- .050 

4- .058 

4- .052 

4- -058 

4- -053 

4- -057 

4- .055 

4- .056 

4- .057 

204 . 

205 . 

— .015 

— .027 

- .015 

- .026 

- .025 

- .017 

i- .026 

- .018 

- .024 

- .018 

- .023 

- .020 

- .022 

- .021 

- .020 

+ .010 

- .002 

4- .010 

- .001 

.000 

4- -010 

4- .001 

4- -010 

4- -004 

4- .009 

4- -004 

4- .009 

4- -007 

4- -008 

4- .009 

200 

+ .030 

4- .018 

4- .030 

4- -019 

4- -020 

4- .028 

4- -019 

4- .026 

4- -020 

4- .025 

4- .020 

4- .024 

4- .022 

4- .022 

4- .023 

207 

— .015 

- .027 

- .016 

- .027 

- .026 

- .018 

;- .027 

- .021 

- .027 

- .022 

- .027 

- .024 

- .026 

— .027 

- .026 

208 

+ .002 

- .010 

4- .002 

- .009 

- .008 

4- .001 

- .008 

.000 

- .006 

.000 

- .005 

- .002 

- .004 

- .003 

- .002 

209 

4- .048 

4- .036 

4- .047 

4- .036 

4- .036 

4- .044 

4- .035 

4- .042 

4- .036 

4- -040 

4- -035 

4- .038 

4- .036 

4- .035 

4- .036 

210. 

- .015 

- .027 

- .016 

- .027 

- .027 

- .019 

- .028 

- .021 

- .027 

- .023 

- .028 

- ..026 

- .028 

— .029 

— .028 

211. 

212. 

213. 

— .010 

— .022 

- .011 

- .022 

- .022 

- .013 

- .022 

- .015 

- .021 

- .017 

- .022 

- .019 

- .021 

- .022 

- .021 

4- .060 

4- .048 

4- -059 

4- .048 

4- -048 

4- .056 

4- -047 

4- .054 

4- -048 

4- -052 

4- .047 

4- .050 

4- -048 

4- .047 

4- .048 

4- -027 

4- .015 

4- .026 

4- -015 

4- -016 

4- -024 

4- -015 

4- .021 

4- .015 

4- .019 

4- .014 
4- .038 
- .029 

4- .017 
4- .040 
- .027 

4- .015 
4- .038 
- .029 

4- -014 
4- .037 
- .031 

4- .015 
4- .038 
- .030 

214 . 

4- -049 
- .010 

4- .037 

4- -048 

4- .037 

4- -037 

4- .046 

4- -037 

4- .044 

4- -038 

4- .043 

215. 

- .022 

- .012 

- .023 

- .023 

- .016 

- .025 

- .021 

- .027 

— .024 

216 

4- .018 

4- .006 

4- .017 

4- .006 

4- -007 

4- .015 

4- -006 

4- .013 

4- .007 

4- .011 

4- -006 

4- .009 

4- .007 

4- .006 

4- .007 

217. 

4- -007 

- .005 

+ .005 
+ 041 

- .006 
4- .030 
- .046 

- .006 
4- .031 

4- .002 
4- .024 

- .007 
4- .015 

- .002 
4- .023 

- .008 
4- .017 

- .003 

- .008 

- .006 

- .008 

— .010 

— .009 

219. 

- .033 

- .045 

- .035 

- .046 

- .037 

1 

- .046 

- .041 

- .047 

- .042 

- .047 

- .045 

- .047 

- .04< 

- .048 



























































































































106 


U. S. COAST AND GEODETIC SUEVEY SPECIAL PUBLICATION NO. 40. 


SUMMARY OF MEAN ANOMALIES FOR VARIOUS DEPTHS OF COMPENSATION AND THE VARIOUS VALUES OF 

EQUATORIAL GRAVITY. 


Depths of eompensation. 

42.6 km. 

66.9 km. 

60.0 km. 

85.3 km. 

Equatorial value of gravity. 

978.030 

978.042 

978.030 

978.041 

978.030 

978.040 

97S. 030 

978.039 

Mean anomalies with regard to sign, using groups. 

Mean anomalies without regard to sign, using groups. 

Mean anomalies with regard to sign, all stations. 

Mean anomalies without regard to sign, all stations. 

Mean anomalies with regard to sign, all stations (Seattle sta¬ 
tions omitted). 

+0.012 
.019 
+ .012 
.022 

+ .013 

.021 

0.000 

.016 

.000 

.020 

+ .001 

.019 

+0.011 
.018 
+ .011 
.021 

+ .012 

.020 

0.000 

.016 

.000 

.020 

+ .001 

.019 

+0.010 

0.000 

.000 

.020 

+ .001 

.019 

+0.009 
.018 
+ .008 
.020 

+ .009 

.020 

0.000 
.017 
- .001 
.020 

.000 

.019 

Mean anomalies without regard to sign, all stations (Seattle sta¬ 
tions omitted). 





Depths of compensation. 

113.7 km. 

127.9 km. 

156.25 km. 

184.6 km. 

Equatorial value of gravity. 

978.030 

978.036 

978.030 

978.035 

978.030 

978.032 

978.030 

978.029 

Mean anomalies with regard to sign, using groups. 

+0.006 

0.000 

+0.005 

0.000 

+0.002 

0.000 

-0.001 

0.000 

Mean anomalies without regard to sign, using groups. 

.018 

.017 

.018 

.017 

.018 

.018 

.019 

.019 

Mean anomalies with regard to sign, all stations. 

+ .005 

- .001 

+ .004 

- .001 

+ .001 

- .001 

- .002 

- .001 

Mean anomalies without regard to sign, all stations. 

Mean anomalies with regard to sign, all stations (Seattle sta¬ 
tions omitted). 

.020 

.020 

.020 

.020 

.020 

.021 

.021 

.021 

+ .006 

.000 

+ .005 

.000 

+ .002 

.000 

- .001 

.000 

Mean anomalies without regard to sign, all stations (Seattle sta¬ 
tions omitted). 

.020 

.019 

.020 

.019 

.020 

.020 

.020 

.020 


The names, elevations, and locations of the stations are given in the table on pages 50-52. 
The values of g-g c for any depth are obtained by combining the correction for topography 
and compensation for that depth given in the table on pages 100 - 102 , with the correction for the 
elevation of the station and the theoretical value of the gravity for the latitude of the station 
computed by the Helmert formula of 1901, which are given on pages 50-52. In this formula the 
value of the first term is 978.030. This is the value in dynes of the intensity of gravity at the 
equator. In order to get the Hayford 1912 anomalies (which were computed by a formula 
which is the same as that of Helmert of 1901, except that the first term is 978.038), add alge¬ 
braically — 0.008 to the g-g c values. For instance, the value of g-g c for station 25 and the 
depth 42.6 km. is —0.005. The 1912 anomaly will be —0.013 dyne. 

The difference at a station between the values of g-g c for any two depths is of the same amount, 
but of opposite sign, to the difference between the effects of topography and compensation for 
the same depths in the table on pages 100 - 102 . 

The differences, g-g c , between the observed gravity and the computed gravity using a 
depth of compensation of 42.6 km. and the Helmert 1901 formula are shown in the second 
column of the preceding table. The mean value of g-g c for this depth was found to be + 0.012 
dyne. In obtaining this mean groups of stations within limited areas were combined and each 
group given unit weight. The third column of the preceding table contains the anomalies for 
the depth 42.6 km. after the mean of the second column, +0.012, has been applied as a correction 
to the first term of Helmert’s formula. These are the most probable anomalies from observa¬ 
tions in the United States if a depth of compensation of 42.6 km. and a flattening of 1/298.2 are 
assumed. The anomalies for the other depths were obtained in a similar manner, except for 
the depth 60.0 km. The anomalies for this depth were obtained from the analytical solution 
lc on page 123. 

The use of 94 additional stations in the United States has changed the value of the first 
term of the United States Coast and Geodetic Survey gravity formula of 1912, based on a depth 
of 113.7 km., only from 978.038 to 978.036. The lowest value of the first term of the gravity 
formula as obtained in the preceding table is 978.029 for the depth of 184.6 km. 

If individual stations are investigated, it will be found that those stations which are in 
mountainous regions and along the coast near deep water have the greatest range in the values 
of g-g c in the preceding table. 

At the end of the table there is given a summary of the mean anomalies for various 
depths of compensation and the several values of equatorial gravity. This shows that the mean 
anomaly with regard to sign when stations near together are combined in groups has the same 
sign and is within 0.001 of the mean of all stations for each depth. It also shows that the Seattle 
stations at which the anomaly is - 0.093 for each have little effect in deciding the character of 
the results. For the purpose of comparison the means with regard to sign are given below for 

































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 107 

the formula derived from the investigation of which special publication No. 12 is a report. 
It has 978.038 as the first term, which is also the value of gravity at the equator. 

The solution by least squares which gave from data in the United States the theoretically 
best value of gravity at the equator and the depth of compensation is discussed on pages 123 
and 124. In the above table there are given the values of the anomalies for the depth thus 
determined, 60 km., although the depth, 56.9 km., gives nearly the same set of values. 

The summary alone gives no strong evidence in favor of any one depth of compensation, 
for the means without regard to sign have little change from one depth to another while the 
mean with regard to sign is made the same (zero) for each depth. 

The means with regard to sign of the anomalies for the different depths based upon the 
United States Coast and Geodetic Survey formula of 1912 are given in the following table: 


Mean anomalies for various depths , based upon the United Slates Coast and Geodetic Survey formula of 1912, 

7 0 =978.038 (1+0.005802 sin 2 <t>-0.000007 sin 2 2$). 


Depths of compensation. 

42.6 km. 

56.9 km. 

60.0 km. 

85.3 km. 

113.7 km. 

127.9 km. 

156.25 km. 

184.6 km. 

Mean anomaly with regard to sign, using groups. 

Mean anomaly with regard to sign, for all stations. 

Mean anomaly with regard to sign, omitting Seattle stations.. 

+0.004 
+ .004 
+ .005 

+0.003 
+ .003 
+ .004 

+0.002 

+0.001 
.000 
+ .001 

-0.002 

- .003 

- .002 

-0.003 

- .004 

- .003 

-0.006 

- .007 

- .006 

-0.009 
- .010 
- .009 


This table is instructive only in showing how the computed value of gravity increases on 
an average with the depth of compensation. 

THE RELATION BETWEEN THE DEPTH OF COMPENSATION AND THE TOPOGRAPHY. 

While the mean anomalies with and without regard to sign, as shown in the summary above 
and the one on page 67, do not give any intimation as to which depth is the most probable one, 
the tables given below do seem to throw some light on this question. 

The first part of the table shows the anomalies for the coast stations for the several depths, 
the second part has similar data for the mountainous stations below the general level, and the 
third one gives the data for mountainous stations above the general level, while the fourth 
and fifth parts of the table give the data for the stations near but not on the coasts and in the 
interior not in mountainous regions, respectively. The computed value in each case from which 
the anomalies were obtained depends upon the theoretical value of gravity at the equator, as 
obtained from all of the 216 stations for the particular depth. 


liayford anomalies for various depths of compensation arranged in groups according to topography. 


Station number 

Hayford anomaly for depth of compensation of— 

42.6 km. 

56.9 km. 

85.3 km. 

113.7 km. 

127.9 km. 

156.25 km. 

184.6 km. 

Twenty-seven coast stations in the order of their distances 
from the 1000 -fathom line: 

54 . 

-0.006 

- 0.010 

-0.017 

- 0.021 

-0.023 

-0.025 

-0.027 

18 . 

- .004 

- .008 

- .014 

- .019 

- .022 

- .025 

- .027 

80 . 

- .010 

- .010 

- .011 

- .011 

- .010 

- .010 

- .009 

90 . 

- .037 

- .039 

- .043 

- .046 

- .048 

- .049 

- .051 

92 . 

+ .016 

+ .015 

+ .013 

+ .012 

+ .011 

+ .010 

+ .010 


+ .019 

+ .015 

+ .010 

+ .007 

+ .005 

+ .003 

+ .002 

125 . 

- .016 

- .018 

- .020 

- .021 

- .023 

- .023 

- .024 


+ .031 

+ .030 

+ .028 

+ .029 

+ .028 

+ .029 

+ .030 

126 . 

- .014 

- .016 

- .019 

- .020 

- .021 

- .022 

- .023 

215 . 

- .022 

- .023 

- .025 

- .027 

- .029 

- .029 

- .030 

149 . 

- .022 

- .024 

- .027 

- .029 

- .031 

- .032 

- .034 

164 . 

- .009 

- .010 

- .011 

- .012 

- .012 

- .012 

- .011 

127 . 

- .004 

- .007 

- .010 

- .012 

- .014 

- .015 

- .017 


- .009 

- .010 

- .011 

- .011 

- .012 

- .011 

- .011 


+ .005 

+ .004 

+ .002 

+ .002 

+ .001 

+ .001 

+ .001 

27 . 

+ .025 

+ .025 

+ .025 

+ .024 

+ .024 

+ .024 

+ .023 

26 . 

+ .027 

+ .027 

+ .026 

+ .026 

+ .025 

+ .026 

+ .025 

66 . 

- .049 

- .049 

- .049 

- .048 

- .049 

- .049 

- .050 


+ .029 

+ .027 

+ .023 

+ .020 

+ .019 

+ .017 

+ .015 

161 . 

- .015 

- .016 

- .018 

- .019 

- .020 

- .021 

- .021 


+ .018 

+ .017 

+ .013 

+ .012 

+ .010 

+ .009 

+ .008 

29 . 

+ .009 

+ .008 

+ .007 

+ .007 

+ .006 

+ .006 

+ .005 

30 . 

+ .009 

+ .009 

+ .007 

+ .007 

+ .006 

+ .006 

+ .005 

17 . 

- .015 

- .016 

- .018 

- .019 

- .020 

- .020 

- .020 


- .009 

- .009 

- .009 

- .007 

- .007 

- .006 

- .004 

159 . 

+ .009 

+ .007 

+ .003 

+ .001 

.000 

- .002 

- .003 

128. 

- .012 

- .013 

- .013 

- .013 

- .013 

- .012 

- .012 


- .002 

- .003 

- .006 

- .007 

- .008 

- .009 

- .009 

Mean without regard to sign. 

.017 

.017 

.017 

.018 

.018 

.018 

.018 


















































































108 U. s. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

Hay ford anomalies for various depths of compensation arranged in groups according to topography Continued. 


Station number 

Hayford anomaly for depth of compensation of— 

42.6 km. 

56.9 km. 

85.3 km. 

113.7 km. 

127.9 km. 

156.25 km. 

184.6 km. 

Thirty-six stations in mountainous regions and below the 








general level arranged in the order of their distances be- 








Tow the general level: 

70. 

+0.003 

-0.001 

-0.006 

-0. 011 

-0.014 

-0.017 

-0.022 

156 . 

- .005 

- .007 

- .011 

- .013 

- .014 

- .016 

- .018 

105. 

- .017 

- .017 

- .018 

- .019 

- .020 

- .020 

- .021 

202. 

+ .023 

4- .023 

4- .023 

4- .023 

4- .023 

4- .023 

4- .022 

67. 

4- .004 

- .001 

- .006 

- .011 

- .014 

- .018 

- .023 

153. 

- .019 

- .020 

- .021 

- .021 

- . 021 

- .021 

- .021 

210. 

- .027 

- .027 

- .028 

- .027 

- .028 

- .028 

- .028 

175. 

- .019 

- .019 

- .021 

- .022 

- .023 

- .025 

- .026 

172. 

- .027 

- .027 

- .031 

- .032 

- .034 

- .036 

- .037 

85. 

- .005 

- .003 

.000 

4- .003 

4- .003 

4- .005 

4- .006 

176. 

- .022 

- .022 

- .022 

- .022 

- .022 

- .021 

- .021 

131. 

- .021 

- .021 

- .022 

- .022 

- .023 

- .024 

- .025 

155. 

- .019 

- .019 

- .019 

- .019 

- .019 

- .019 

- .019 

201. 

4- .023 

4- .025 

4- .029 

4- .032 

4- .033 

4- .035 

4- .038 

63. 

+ .009 

4- .009 

4- .009 

4- .009 

4- .009 

4- .009 

4- .008 

198. 

4- .051 

4- .053 

4- .054 

4- .056 

4- .056 

4- .057 

4- .057 

113. 

- .033 

- .031 

- .028 

- .025 

- .025 

- .023 

- .021 

130. 

- .038 

- .038 

- .037 

- .037 

- .037 

- .037 

- .038 

112. 

4- .025 

4- .028 

4- .032 

4- .035 

4- .035 

4- .038 

4- .039 

110. 

- .004 

- . 0u6 

- .010 

- .013 

- .014 

- .016 

- .019 

Ill. 

- .016 

- .019 

- .023 

- .026 

- .027 

- .028 

- .029 

117. 

+ .031 

4- .034 

4- .037 

4- .038 

4- .038 

4- .039 

4- .039 

115. 

- .009 

- .007 

- .007 

- .007 

- .008 

- .009 

- .012 

109. 

4- .032 

4- .034 

4- .034 

4- .034 

4- .033 

+ .032 

4- .031 

82. 

4- .022 

4- .020 

-f~ • 018 

4- .015 

4- .014 

4- .012 

4- .008 

45. 

4- .039 

4- .037 

4- .030 

4- .022 

4- .018 

4- .012 

4- .004 

194. 

4- .003 

4- .006 

4- .010 

4- .013 

4- .014 

4- .017 

4- .018 

42. 

4- .006 

4- .003 

- .001 

- .005 

- .007 

- .010 

- .015 

195. 

4- .024 

4- .024 

4- .023 

4- .021 

4- .019 

4- .017 

4- .013 

49. 

4- .009 

4- .010 

4- .012 

4- .012 

4- .012 

4- .012 

4- .010 

44. 

- .020 

- .017 

- .014 

- .014 

- .015 

- .016 

- .018 

79. 

- .003 

4- .001 

4- .006 

4- .010 

4- .011 

4- .014 

4- .015 

78. 

- .004 

- .001 

4- .002 

4- .004 

4- .005 

+ .006 

4- .007 

69. 

.000 

- .001 

- .005 

- .008 

- .010 

- .012 

- .017 

46. 

4- .019 

4- .023 

4- .026 

4- .026 

4- .025 

4- .025 

4- .022 

47. 

- .032 

- .027 

- .022 

- .019 

- .018 

- .017 

- .017 

Mean with regard to sign. 

.000 

.000 

.000 

- .001 

- .001 

- .002 

- .003 

Mean without regard to sign. 

.018 

.018 

.019 

.020 

.021 

.021 

.022 

Twenty stations in mountainous regions and above the 








general level arranged in the order of their distances above 








the general level: 








129. 

- .009 

- .011 

- .014 

- .016 

- .017 

- .018 

- .019 

71. 

4- .020 

4- .016 

4- .010 

4- .005 

4- .002 

- .001 

— .006 

116. 

4- .002 

— .003 

— .012 

- .019 

- .023 

- .028 

— .033 

101 . 

4- .046 

+ .045 

4- .043 

4- .042 

4- .041 

4- .041 

4- .040 

52. 

4- .019 

4- .015 

4- .008 

4- .001 

- .003 

- .007 

- .013 

51. 

4- .043 

4- .038 

4- .030 

4- .023 

4- .019 

4- .014 

4- .009 

48. 

4- .026 

4- .021 

4- .013 

4- .006 

4- .003 

— .001 

— .005 

152. 

4- .013 

4- .009 

4- .002 

— .003 

— .005 

— .008 

— .011 

50. 

4- .023 

4- . 01S 

-f- .008 

.000 

— .004 

— .009 

— .015 

98. 

4- .037 

4- .034 

4- .028 

4- .023 

4- .021 

4- .018 

4- .015 

64. 

- .036 

- .040 

- .045 

- .048 

- .049 

- .050 

- .052 

20 . 

4- .026 

4- .022 

4- .015 

4- .012 

4- .010 

4- .008 

4- .006 

86 . 

4- .020 

4- .016 

4- .011 

4- .008 

4- .007 

4- .005 

4- .004 

103 . 

- .006 

- .012 

- .021 

- .027 

- .029 

- .033 

- .036 

75. 

4- .067 

4- .062 

4- .057 

4- .054 

4- .052 

4- .051 

4- .050 

68. 

4- .015 

4- .012 

4- .007 

4- .003 

4- .001 

- .001 

- .006 

114 . 

4- .011 

4- .001 

- .015 

- .026 

- .032 

- .039 

— .047 

55 . 

4- .021 

4- .014 

4- .004 

- .001 

- .004 

- .007 

- .009 

102 . 

4- .028 

4- .022 

4- .012 

4- .006 

4- .003 

- .001 

- .004 

43 . 

4- .057 

4- .046 

4- .032 

4- .023 

4- .019 

4- .013 

4- .006 

Mean with regard to sign . 

4- .021 

4- .016 

4- .009 

4- .003 

4- .001 

- .003 

- .006 

Mean without regard to sign . 

.026 

.023 

.019 

.017 

.017 

.018 

.019 

Forty-six stations near the coast, in the order of their dis- 








tances from the open coast: 








157. 

- .024 

- .026 

- .032 

- .034 

- .036 

- .038 

- .040 

31. 

- .007 

- .007 

- .007 

- .006 

- .007 

- .005 

- .005 

25. 

- .017 

- .017 

- .017 

- .017 

- .018 

- .017 

- .018 

93 . 

- .041 

- .042 

- .043 

- .042 

- .042 

- .042 

- .042 

217 . 

- .005 

- .006 

- .007 

- .008 

- .008 

- .008 

- .009 

23 . 

— .010 

— .009 

— 009 

009 

0OQ 

OOK 

0Q8 

28 . 

- .013 

- .015 

- .016 

- !oi8 

- !oi9 

- .020 

- .021 

160 . 

— .006 

— .008 

— .010 

— 012 

013 

014 

015 

24. 

+ .024 

4- .024 

4- 024 

-f 024 

-f 023 

-f 023 

-f 023 

124. 

- .026 

- .027 

- .029 

- .031 

- ! 032 

- !033 

- .034 

















































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


109 


Hay ford anomalies for various depths of compensation arranged in groups according to topography —'Continued. 


St ation number 


Hayford anomaly for depth of compensation of— 


42.6 km. 

56.9 km. 

85.3 km. 

113.7 km. 

127.9 km. 

156.25 km. 

184.6 km. 

Forty-six stations near the coast, in the order of their dis¬ 
tances from the open coast—Continued. 








158. 

-0.008 

-0.010 

-0.013 

-0.015 

-0.016 

-0.018 

-0.019 

148. 

- .011 

- .012 

- .015 

- .016 

- .017 

- .018 

- .019 

81. 

+ .016 

4- .010 

.000 

- .008 

- .012 

- .018 

- .024 

147. 

+ .017 

+ .016 

+ .015 

4- .015 

+ .014 

4- .014 

4- .014 

150. 

+ .005 

-I- .005 

+ .004 

+ .004 

+ .004 

+ .004 

4- .003 

146. 

+ .005 

4- .005 

4- .005 

+ .005 

4- .005 

4- .005 

4- .005 

213. 

+ .015 

+ .015 

+ .015 

4- .015 

+ .014 

+ .015 

4- .015 

173. 

- .008 

- .009 

- .010 

- .009 

- .010 

- .009 

- .008 

209. 

4- .036 

+ .036 

+ .035 

+ .036 

+ .035 

+ .036 

4- .036 

21. 

+ .037 

+ .037 

+ .038 

+ .039 

+ .039 

+ .040 

4- .040 

22. 

+ .039 

+ .039 

4- .040 

+ .041 

4- .040 

+ .041 

4- .041 

163. 

4- .005 

+ .005 

+ .004 

+ .004 

4- .004 

4- .004 

4- .004 

145. 

+ .016 

4- .016 

+ .015 

+ .016 

+ .015 

4- .016 

4- .017 

84. 

+ .037 

4- .038 

+ .038 

4- .039 

4- .039 

4- .040 

4- .040 

216. 

+ .006 

+ .006 

+ .006 

+ .007 

+ .006 

4- .007 

4- .007 

144. 

- .006 

- .006 

- .006 

- .004 

- .004 

- .003 

- .001 

212. 

4- .048 

+ .048 

4- .047 

4- .048 

+ .047 

4- .048 

4- .048 

214. 

+ .037 

+ .037 

+ .037 

4- .038 

4- .038 

4- .038 

4- .038 

91. 

+ .037 

+ .038 

+ .038 

+ .038 

+ .037 

4- .037 

4- .037 

9. 

- .025 

- .025 

- .021 

- .018 

- .017 

- .015 

- .014 

65. 

+ .003 

4- .005 

+ .008 

+ .011 

+ .012 

4- .014 

4- .016 

97. 

- .015 

— .014 

- .012 

- .010 

- .009 

- .007 

- .005 

123. 

- .043 

- .042 

- .041 

- .041 

- .042 

- .042 

- .042 

16. 

+ .015 

4- .016 

+ .017 

+ .017 

+ .016 

4- .017 

4- .017 

10. 

- .010 

- .009 

- .008 

- .006 

- .006 

- .001 

- .002 

11. 

- .012 

- .011 

- .010 

- .008 

- .007 

- .006 

- .004 

19. 

- .013 

- .012 

- .012 

- .011 

- .012 

- .012 

- .012 

151. 

+ .030 

4- .029 

4- .028 

4- .027 

+ .027 

4- .026 

4- .025 

219. 

- .045 

- .046 

- .046 

- .047 

- .047 

- .047 

- .048 

162. 

+ .021 

-f .021 

+ .021 

4- .021 

+ .021 

4- .022 

4- .022 

165. 

- .019 

- .020 

- .022 

- .023 

- .023 

- .023 

- .023 

32. 

- .021 

- .021 

- .021 

- .021 

- .021 

- .021 

- .021 

94. 

- .019 

- .018 

- .017 

- .015 

- .015 

- .013 

- .012 

62. 

+ .037 

-f .035 

4- .033 

4- .033 

+ .032 

4- .032 

4- .032 

106. 

- .016 

- .015 

- .013 

- .011 

- .011 

- .009 

- .008 

6. 

+ .015 

4- .016 

+ .017 

+ .018 

4- .019 

4- .020 

4- .022 

Mean with regard to sign. 

+ .002 

4- .002 

+ .001 

+ .001 

+ .001 

4- .001 

4- .001 

Mean without regard to sign. 

.020 

.020 

.020 

.020 

.020 

.021 

.021 

E ighty-seven stations in the interior and not in mountain¬ 
ous regions, arranged in the order of elevation: 




- .010 

- .009 

- .007 

- .005 

167. 

- .014 

- .013 

- .012 

95. 

- .005 

- .003 

.000 

+ .003 

4- .004 

4- .007 

4- .009 

168. 

+ .010 

+ .011 

+ .012 

+ .015 

+ .015 

4- .018 

4- .020 

88. 

- .016 

- .014 

- .011 

- .008 

- .008 

- .005 

- .003 

13. 

+ .024 

+ .026 

+ .029 

+ .032 

+ .033 

4- .035 

4- .037 

142. 

+ .007 

+ .008 

4- .011 

+ .013 

+ .014 

4- .016 

4- .019 

87. 

+ .020 

+ .020 

4- .021 

4- .023 

+ .023 

4- .024 

-f* . 025 

141. 

- .021 

- .019 

- .016 

- .014 

- .013 

- .011 

- .009 

132. 

- .026 

- .025 

- .024 

- .023 

- .023 

- .022 

- .020 

35. 

- .012 

- .011 

- .009 

- .007 

- .006 

- .004 

- .002 

38 . 

- .010 

- .008 

- .006 

- .003 

- .002 

.000 

4- .003 

169 . 

+ .011 

+ .012 

4- .013 

+ .015 

4- .015 

4- .017 

4- .019 

120 . 

- .010 

- .009 

- .009 

- .006 

- .006 

- .003 

- .001 

170 . 

-j- . 005 

4- .006 

+ .006 

4- .008 

+ .008 

4- .010 

4- .011 

89. 

- .020 

- .020 

- .019 

- .018 

- .017 

- .016 

- .014 

174 . 

- .029 

- .030 

- .031 

- .031 

- .031 

- .030 

- .030 

177 . 

- .002 

- .001 

4- .001 

+ .003 

+ .003 

4- .006 

4- .008 

179 . 

- .030 

- .028 

- .026 

- .023 

- .022 

- .020 

- .018 

36 . 

- .011 

- .010 

- .007 

- .005 

- .005 

- .003 

- .002 

138. 

- .019 

- .018 

- .016 

- .014 

- .013 

- .011 

- .008 

104 . 

- .027 

- .025 

- .024 

- .022 

- .022 

- .021 

- .021 

. 

- .024 

- .024 

- .023 

- .022 

- .022 

- .021 

- .021 

143 . 

4- .016 

+ .017 

+ .018 

4- .020 

4- .020 

4- .022 

4- .023 

134 . 

- .028 

- .028 

- .027 

- .025 

- .025 

- .023 

- .022 

166. 

- .021 

- .021 

- .022 

- .021 

- .022 

- .021 

- .021 

181 . 

+ .013 

4- .014 

+ .016 

+ .017 

+ .018 

4- .020 

4- .022 

207 . 

- .027 

- .027 

- .027 

- .027 

- .027 

- .026 

- .026 

14 . 

+ .025 

4- .026 

+ .027 

+ .028 

4- .028 

4- .029 

4- .030 

33. 

203. 

- .005 

- .004 

- .002 

- .001 

- .001 

4- .001 

4- .003 

+ .047 

4- .048 

+ .050 

+ .052 

4- .053 

4- .055 

• 05 1 

137. 

178 . 

+ .001 

4- .001 

4- .001 

+ .003 

4- .003 

4- .004 

+ .006 

.000 

4- .001 

+ .001 

4- .003 

+ -004 

4- .006 

4- .007 

73. 

136. 

211. 

4- .002 

+ .003 

4- .004 

+ .007 

4- .007 

4- .009 

4- .011 

- .013 

- .012 

- .011 

- .010 

- .010 

- .009 

- .008 

- .022 

- .022 

- .022 

- .021 

- .022 

- .021 

- .021 






































































































110 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


Hay ford anomalies for various depths of compensation arranged in groups according to topography —Continued. 


Hayford anomaly for depth of compensation of- 


station numDer 

42.6 km. 

56.9 km. 

85.3 km. 

113.7 km. 

127.9 km. 

156.25 km. 

184.6 km. 

Eighty-seven stations in the interior and not in mountain¬ 
ous regions arranged in the order of elevation—Contd. 








121. 

0.000 

+0.001 

+0.002 

+0.004 

+0.004 

+0.006 

+0.008 

12. 

- .030 

- .029 

- .027 

- .025 

- .024 

- .022 

- .020 

59. 

+ .012 

+ .014 

-P .017 

+ .021 

+ .022 

+ .025 

+ .028 

34. 

- .022 

- .020 

- .019 

- .017 

- .017 

- .016 

- .015 

74. 

+ .054 

+ .056 

+ .058 

+ .061 

+ .062 

+ .065 

+ .067 

191. 

-f* • 005 

+ .007 

+ .010 

+ .013 

+ .015 

+ .017 

+ .020 

133. 

- .023 

- .024 

- .027 

- .028 

- .029 

- .030 

- .031 

37. 

- .007 

- .006 

- .005 

- .003 

- .003 

- .001 

.000 

39. 

- .021 

- .019 

- .016 

- .014 

- .013 

- .010 

- .008 

154. 

- .033 

- .034 

- .036 

- .036 

- .037 

- .038 

- .038 

171. 

- .026 

- .026 

- .027 

- .027 

- .027 

- .027 

- .026 

196. 

4- .033 

+ .034 

+ .035 

+ .038 

+ .038 

+ .040 

+ .042 

140. 

+ .015 

+ .015 

+ .016 

+ .018 

+ .019 

+ .020 

+ .022 

184. 

- .030 

- .029 

- .028 

- .025 

- .024 

- .022 

- .020 

180. 

- .043 

- .043 

- .042 

- .040 

- .040 

- .038 

- .037 

122. 

+ .010 

+ .011 

+ .011 

+ .013 

+ .013 

+ .014 

+ .016 

200. 

+ .003 

+ .004 

+ .006 

+ .008 

+ .009 

+ .012 

+ .014 

199. 

+ .013 

+ .014 

+ .016 

+ .019 

+ .020 

+ .023 

+ .025 

15. 

- .021 

- .021 

- .022 

- .021 

- .021 

- .021 

- .021 

197. 

+ .003 

+ .004 

+ .005 

+ .008 

+ .009 

+ .011 

+ .013 

119. 

+ .011 

+ .012 

-+■ . 01o 

+ .017 

+ .018 

+ .021 

+ .022 

182. 

- .052 

- .052 

- .050 

- .048 

- .047 

- .046 

- .044 

208. 

- .010 

- .009 

- .008 

- .006 

- .005 

- .004 

- .002 

204. 

- .027 

- .026 

- .026 

- .024 

- .023 

- .022 

- .020 

108. 

- .011 

- .009 

- .007 

- .004 

- .003 

.000 

+ .002 

185. 

+ .010 

+ .011 

+ .012 

+ .014 

+ .015 

+ .017 

+ .019 

96. 

218 a. 

- .052 

- .052 

- .051 

- .050 

- .049 

- .048 

- .046 

183. 

- .050 

- .049 

- .048 

- .047 

- .046 

- .044 

- .043 

139. 

+ .012 

+ .012 

+ .012 

+ .013 

+ .014 

+ .015 

+ .016 

186. 

+ .007 

+ .008 

+ .011 

+ .014 

+ .015 

+ .018 

+ .021 

60. 

- .005 

- .004 

- .001 

+ .003 

+ .004 

+ .007 

+ .010 

58. 

+ .023 

+ .023 

+ .023 

+ .025 

+ .025 

+ .027 

+ .028 

189. 

+ .027 

+ .029 

+ .031 

+ .034 

+ .036 

+ .038 

+ .040 

118. 

-f .006 

+ .008 

+ .012 

+ .016 

+ .017 

+ .021 

+ .024 

57. 

+ .042 

+ .041 

+ .040 

+ .040 

+ .039 

+ .040 

+ .041 

40. 

+ .009 

+ .011 

+ .013 

+ .016 

+ .017 

+ .020 

+ .022 

107. 

+ .027 

+ .026 

+ .025 

+ .026 

+ .026 

+ .027 

+ .028 

205. 

- .002 

- .001 

+ .001 

+ .004 

+ .004 

+ .007 

+ .009 

76. 

- .002 

- .001 

+ .002 

+ .004 

+ .005 

+ .008 

+ .010 

190. 

+ .013 

+ .014 

+ .016 

+ .019 

+ .020 

+ .023 

+ .025 

192. 

+ .012 

+ .014 

+ .017 

+ .021 

+ .022 

+ .025 

+ .028 

61. 

- .027 

- .028 

- .028 

- .027 

- .027 

- .027 

- .026 

77. 

+ .020 

+ .023 

+ .026 

+ .031 

+ .032 

+ .036 

+ .038 

72. 

+ .032 

+ .033 

+ .033 

+ .034 

+ .034 

+ .035 

+ .036 

193. 

•4“ . 025 

+ .027 

+ .030 

+ .032 

+ .033 

+ .036 

+ .037 

206. 

+ .018 

+ .019 

+ .019 

+ .020 

+ .020 

+ .022 

+ .023 

187. 

+ .012 

+ .013 

+ .014 

+ .017 

+ .018 

+ .020 

+ .022 

188. 

+ .034 

+ .035 

+ .036 

+ .037 

+ .037 

+ .039 

+ .039 

83. 

- .008 

- .006 

- .005 

- .004 

- .003 

- .002 

- .001 

100. 

- .019 

- .017 

- .016 

- .015 

- .015 

- .014 

- .014 

41. 

- .009 

- .009 

- .010 

- .010 

- .010 

- .009 

- .009 

99. 

- .012 

- .013 

- .014 

- .014 

- .015 

- .015 

- .017 

Mean with regard to sign. 

- .003 

- .002 

- .001 

+ .001 

+ .001 

+ .003 

+ .005 

Mean without regard to sign. 

.018 

.019 

.019 

.019 

.019 

.020 

.021 


o Not computed. 


The mean value of the anomalies with regard to sign for the extreme depths for the coast 
stations is -0.002 for a depth of 42.6 km., and -0.009 for the depth of 184.6 km. The inter¬ 
mediate depths have values which fall between those two. This is an indication that at 
the coast the smallest depth is nearest the truth. These stations show a negative mean value 
for each depth which agrees with what are called the Hayford 1912 anomalies. (See p. 63.) 
This is as might be expected on account of the lighter material in the Cenozoic formation which 
is generally present along the coast. (See p. 76.) 

The second table shows mean anomalies with regard to sign which are very close to zero. 
These are at stations in mountainous regions below the general level. The total range is 
only 0.003. There is no one depth which seems to be much more probable than an^- other. 

The third table shows that the means with regard to sign for the anomalies at mountain 
stations above the general level have a total range of 0.027. They vary from +0.021 for depth 














































































Special Publication, No. 40. 



FIG. 5.—GRAPHIC DETERMINATION OF THE MOST PROBABLE DEPTH OF COMPENSATION FROM 216 STATIONS 

IN THE UNITED STATES. 


































































































Special Publication No. 40- 



30 4-0 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 

Depth of Compensation in Ki/ometers 


FIG. 6.—GRAPHIC DETERMINATION OF THE MOST PROBABLE DEPTH OF COMPENSATION FROM UNITED STATES 

STATIONS EAST OF THE NINETY-EIGHTH MERIDIAN. 






























































Special Publication No. 40. 



20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 

Depth of Compensation in Kilometers 

FIG. 7.—GRAPHIC DETERMINATION OF THE MOST PROBABLE DEPTH OF COMPENSATION FROM UNITED STATES 

STATIONS WEST OF THE NINETY-EIGHTH MERIDIAN. 



















































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


Ill 


42.6 km. to —0.006 for depth 184.6 km. The evidence here is strongly in favor of the greater 
depths. 

The stations near but not on the coast have means which are close to zero for each depth. 
The range is from +0.002 for the depth 42.6 km. to +0.001 for the depth 184.6 km. 

The stations in the interior not in mountainous regions have mean anomalies which range 
from — 0.003 for the depth 42.6 km. to + 0.005 for the depth 184.6 km. The intermediate depths 
have means which in no case are more than 0.003 from zero. The evidence from these stations 
is slightly in favor of the intermediate depths. 

It is highly improbable that there should be tw r o depths in mountainous regions, one for 
the higher land and one for the valleys, although it is possible that there may be a different 
depth in the mountainous regions than in the flat portions of the country. 

We must conclude, therefore, that a depth of 42.6 or 56.9 km. is very improbable in the 
mountainous regions, for the mean values with regard to sign for the stations above the general 
level are +0.021 and +0.016 for those two depths, respectively, while for the stations below T 
the general level the means are 0.000 and 0.000. There seems to be no evident explanation for 
this difference, aside from the effect of the depth, as the stations in any one of the topographic 
groups do not fall largely in any one geologic formation, as do the coast stations. 

The depth 184.6 km. gives mean values of — 0.006 for the high stations and — 0.003 for the low 
ones. While these values agree quite closely, yet they differ an appreciable amount from the 
means of all of the 219 anomalies in the whole country. 

The depth which seems to give the smallest mean values for the two groups is 127.9 km. 
The mean for the high stations in mountainous regions for this depth is +0.001 and for low 
stations it is —0.001. 

The data given in the table on pages 107 to 110, which show the relation between the 
anomalies and the topography indicate that the depths 42.6 and 184.6 km. are not so near the truth 
as are intermediate values. They also seem to indicate that the value is probably over 100 km. 
It is realized by the author that this conclusion is contrary to that arrived at from the deter¬ 
mination of the most probable depth from the 216 stations by the method of least squares (see 
p. 123), which is 60 km. w r hen the flattening, 1/298.2, is held fixed, or 70.9 km. when the 
flattening also is determined by the solution. It is believed that the portion of the anomalies 
at coast stations due to the presence of the Cenozoic geologic formation with densities less than 
normal had a considerable part in making the depth from all the 216 stations as low as 60 km. 

GRAPHIC DETERMINATION OF THE MOST PROBABLE DEPTH OF COMPENSATION. 

According to the theory of probabilities the most probable depth of compensation is that one 
for which the sum of the squares of the residuals or anomalies is a minimum. The residuals are 
of course assumed to be due only to accidental errors, and hence are as apt to be positive as nega¬ 
tive. The values in the table on pages 103-105, in the columns headed g— (g c + 12), g— (g c + 11), 
etc., were used in obtaining the sum of the squares of the anomalies for each of the depths. 

The sum of the squares is smaller for the smallest two depths of compensation than for the 
other depths given in the table. The equation of the curve which most nearly fits the sums of 
the squares for the different depths was derived and its minimum point comes at the depth of 
57.1 km. 

The sums of the squares for the several depths were also plotted on figure 5, and a curve 
was drawn through the several points. The lowest point on the curve falls between the depths 
42.6 km. and 56.9 km., and the value of the depth at the lowest point is 55.5 km., with an 
uncertainty from plotting and scaling of about 4 km. This value is only 1.6 km. from the 
minimum point of the curve as found above from its equation. 

A depth for the eastern half of the United States (east of the ninety-eighth meridian) was 
determined by plotting the sum of the squares on figure 6. The lowest point of the curve falls 
at a depth of 62 km. The uncertainty of the plotting and scaling is not more than about 4 km. 

Likewise a depth was determined for the western half of the United States, as shown in 
figure 7. Here the minimum point on the curve falls at the depth 48 km., with an uncertainty 
from plotting and scaling of about 4 km. 


112 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


An analysis of the table giving the anomalies for the different topographic groups (see pp. 
107 to 110) makes it apparent that the results at those stations near but not on the coast and at 
those in the interior which are not in mountainous regions above the general level, are not more 
strongly in favor of one depth than any other. This fact causes the influence of the mountain 
stations above the general level to be less than the plains stations in a determination of the 
most probable depth of compensation where all stations are involved. This is due to the fact 
that there are only 20 stations in mountainous regions above the general level, while there are 
169 stations in the groups mentioned above. 

As the mountain stations are more sensitive to a change in the depth of compensation, it 
was decided to determine graphically the most probable depth from those stations alone, 56 in 
number. The resulting curve for these stations is shown in figure 8. The plotted points are 
the sum of the squares of the residuals or anomalies. These are based on a value of gravity at 
the equator so derived from all stations in the United States as to make the mean anomaly for 
the United States zero. The depth determined from this curve is 104 km. which differs ma¬ 
terially from the depths obtained from the other three curves (figs. 5, 6 and 7) which were 
between 48 and 62 km. 

An analytical solution of the problem was also made. In this solution the mean flattening 
was held fixed as in the graphical determination, but the gravity at the equator was determined 
from the 56 stations themselves instead of from all the stations in the United States. The 
depth determined was 94.9 lan., only 9 km. from the value obtained graphically in spite of the 
difference in methods and assumptions. 

It is interesting that the depths obtained by Hayford from deflections of the vertical in 
several groups (Nos. 14, 8, 7, and 4) of stations in mountainous regions are 84, 66, 152, and 
85 Ion. The value is 97 if a straight mean for the 4 groups is taken. This agrees well with the 
values determined analytically from gravity data for mountainous regions, which for the 56 
stations is 94.9 km. 

The sums of the squares of the anomalies, for the several depths, for the 20 stations in 
mountainous regions above the general level were plotted on figure 9 and the minimum point 
of the curve drawn through the plotted points gives the most probable depth as 124 km. This 
value is only 20 lan. different from the most probable depth obtained graphically from the data 
for all mountain stations. 

The values from the analytical determinations of the most probable depths of compensation 
from all of the stations in the United States, in the eastern half of this country, in the western 
half, and in the mountainous regions agree well with those from the graphic solutions dis¬ 
cussed above. See pages 113 to 131 for the analytical determination of the depth of compen¬ 
sation, the flattening of the earth, and the theoretical value of gravity at the equator. 

The stations not in the United States were not used to obtain the most probable depth of 
compensation, as the necessary data for them were not available. 

The author is inclined to favor the depth of 94.9 km. as being nearer the truth than the 
lower depths, and besides it agrees more nearly with the depth as obtained from deflections of 
the vertical by Hayford. 0 We may conclude that the most probable depth of the compensa¬ 
tion as derived from the gravity data is 94.9 km. 

It is believed that the value, 97 lan., obtained by Hayford from deflections of the vertical 
in mountainous regions is nearer the truth for the average depth of compensation than his 
values 113.7 and 120 km. If the depth from gravity data and the depth 97 km. mentioned 
above are given equal weight the mean depth of compensation is 96 km. which the author 
believes is the best one available from all geodetic data. 

This value, of course, must not be considered as having extreme accuracy, for no doubt a 
depth determined from much more gravity and deflection data would be different. The author 
believes that future determinations of the depth from more extensive data will fall between 80 
and 130 km. 

a See Figure of the Earth and Isostasy from Measurements in the United States, and Supplementary Investigation in 1909 of the Figure of the 
Earth and Isostasy, J. F. Hayford, 1909. 



Special Publication No. 40. 



30 VO 50 60 70 80 90 100 HO 120 130 140 150 160 170 180 130 


Depth of Compensation /n Kilometers 

FIG. 8.—GRAPHIC DETERMINATION OF THE MOST PROBABLE DEPTH OF COMPENSATION FROM 56 UNITED STATES 

STATIONS IN MOUNTAINOUS REGIONS. 



















































































Sum of Squares of ffesidua/s 


Special Publication No. 40. 



30 40 50 60 70 80 90 100 110 IZO 130 140 150 160 170 180 190 

Depth of Compensation /n K//ometers 


FIG. 9.—GRAPHIC DETERMINATION OF THE MOST PROBABLE DEPTH OF COMPENSATION FROM 20 UNITED STATES 
STATIONS IN MOUNTAINOUS REGIONS AND ABOVE THE GENERAL LEVEL. 


























































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


113 


CONSTANTS FOR THE GRAVITY FORMULAS AND THE MOST PROBABLE DEPTHS OF COMPENSATION 
DERIVED BY ANALYTICAL METHODS FROM GRAVITY DATA. 

The method of computing the factors by which the effect of topography and compensation 
was obtained for various depths of compensation, together with the computed effects of these 
changes of depth and the anomalies for the several depths are given on pages 97-106. The fol¬ 
lowing analytical solution was made to determine the constants for the gravity formulas and 
to determine the most probable depths of compensation. 

The formula for y 0 , the theoretical gravity at sea level in geographic latitude <p, may be 
written in the form 

7o = Y e (l + B sin 2 B i sin 2 2<£) (1) 

Yc is the gravity at the equator at sea level, B and B i are coefficients, the former determined from 
gravity observations, the latter found theoretically by Darwin and Wiechert from the assump¬ 
tion that the internal strata of the earth have the same form as if they were completely fluid. 
Their results, based on different laws of internal density, agree in giving £ B 4 = 0.000007, which 
will be used throughout the publication. 

Helmert’s determination of the constants gives for his formula of 1901 on the Potsdam 
system 

7 0 = 978.030 (1 + 0.005302 sin 2 <p - 0.000007 sin 2 2 <p) (2) 

If a value be assumed for the equatorial radius of the earth, the ellipticity or flattening of 
the earth, denoted by/, may be found from the formula, 




( 3 ) 


In this formula B and B 4 are the same quantities as in formula ( 1 ) and to is the ratio of the 

u 2 A. 

centrifugal force of the earth’s rotation at the equator to gravity at the equator, or to = — • co is 

Y« 

the angular velocity in radians, expressed in the time unit used in 7 0 . A is the equatorial radius of 

5 

the earth expressed in the linear unit used in y 0 . The simple formula/ = — B is known as Clair- 

aut’s equation. The above formula is derived from Helmert (Holiere Geodasie, Vol. II, p. 83), 
and may be termed Clairaut’s formula, extended to terms of the second order. The value of 

/= 0 no o was originally given by Helmert as derived from his formula of 1901. This is based on 

Bessel’s equatorial radius of the earth. A larger value of this quantity such as best represents 

modern observations gives/= The value of A used in deriving the values from the 

gravity observations treated in this work is 6378388 meters, from Hayford’s “ Supplementary 
Investigation in 1909 of the Figure of the Earth and Isostasy,” page 60. 

Equation (1) may be transformed into a shape somewhat more convenient for the purpose 
in hand, namely, 

y 0 = G — 6 cos 2 4> + d cos 2 2 <j> (4a) 

The significance of the constants of the new form and the relations between them and those 
of the old are, 

(7 = gravity at latitude 45° = y t ( 1 + 7 ^ — ) 


25 = polar gravity minus equatorial gravity =y 0 B 
d=\ y t B 4 , which to the degree of accuracy involved in the theoreti¬ 


cal developments for B 4 may, like Z? 4 , be considered as constant 
Also 7 t = G—bAd 

26 


And 


B = 


G-b + d 


(4b) 

(4c) 


59387°—17-8 





114 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Let the subscript zero affixed to G, B, and b denote those numerical values corresponding 
to Helmert’s formula of 1901, also G=G 0 + x and b = b 0 + y signify the values determined from 
the observations; x is the correction to gravity at latitude 45°, y is half the correction to the 
quantity, polar gravity minus equatorial gravity. 

Then, 

(2 0 = 980.61591 dynes and b 0 -= 2.59276 dynes 


With these Helmert values, equation (4) becomes 


7 0 = 980.61591 - 2.59276 cos 2 <£ + 0.00685 cos 2 2 <f> (5) 

/ 

or with the corrections applied 


7 0 = 980.61591 +x — (2.59276 +y) cos 2 <£ + 0.00685 cos 2 2 <£ (6a) 


Let g be the observed value of gravity and g c ' the value of gravity computed from (2) or 
its equivalent (5), including corrections for elevation, topography, and compensation for a fixed 
depth. 

Let n' = g — g c ' the gravity anomaly corresponding to formula (2) or (5). The value of 
gravity computed from the corrected formula is g c ' +x — y cos 2 <£ 

An observation of the general form is 
Observed value minus computed value = residual ( v ) 
whence 

g-(9c'+x-y cos 2 <£) = rO 

or >- (6b) 

x — y cos 2 <£—ti/ = —v J 


This is the form of an observation equation for a particular gravity station if the depth of com¬ 
pensation be considered fixed. 

If the assumed depth ( t ) be considered subject to a correction (z), then n' depends on z. 
To put the equation in linear form, let c be the rate of change with regard to depth of the total 

correction for topography and compensation of the station in question or c= since it is only 


through this correction for topography and compensation that g c is affected by a change in t. 
Then if g c be the computed gravity at a depth t + z sufficiently near to the assumed depth t 


g c =9c f +cz 

and replacing g c ' in (6b) by this value of g c there results 


x — y cos 2 <t> + cz — n'= — v (7) 

which is the form of observation equation when a corrected depth of compensation is to be 
determined. 

These observation equations are shown in the following table. Further explanations follow 
immediately after the table. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


115 


Observation equations for obtaining corrections to the coefficients of the gravity formula and to the depth of compensation. 


Station number 

Double 

latitude 

20 

Coefficient of— 

Constant term for solution number— 

X 

y 

2 

1 

2 

3 

4 

5 

6 

7 

8 

17 In. 

o 

37 

9 

47.5 

+1 

-0.790 









-6.3 

18 In. 

40 

58.2 

+1 

- .755 









- .6 

5 Ina. 

41 

51.7 

+1 

- .745 









—2.7 

39 Tn«. 

42 

00.0 

+1 

- .743 









- 2.0 

88 In. 

42 

27.9 

+ 1 

- .738 









+ .2 

26 In a. 

42 

36.7 

+1 

- .736 









—3.2 

4 In. 

42 

43.0 

+1 

- .735 









+ .3 

8 In a. 

42 

56.3 

+1 

- .732 









—3.1 

50 Ina. 

43 

39.0 

4-1 

- .724 









-4.7 

9 In'*. 

43 

48.3 

4-1 

- .722 









-3.9 

13 Ina. 

44 

07.8 

4-1 

- .718 









—1.4 

98 In. 

44 

11.0 

4-1 

- .717 









—3. 7 

99 In a. 

44 

23.0 

4-1 

- .715 









- 2.4 

72 In a. 

44 

26.7 

4-1 

- .714 









- .5 

73 Ina. 

44 

47.3 

4-1 

- .710 









+ 1.9 

65 In®. 

45 

06.3 

4-1 

- .706 









+ 1.4 

37 Ina. 

45 

30.0 

4-1 

- .701 









— 2.1 

84 Ina. 

45 

33.4 

4-1 

- .700 









- .9 

43 In®. 

46 

17.8 

4-1 

- .691 









- 3.1 

106 Ina. 

46 

22.0 

4-1 

- .690 









+ 1.0 

12 Ina. 

46 

31.9 

4-1 

- .688 









— 2.2 

91 In. 

46 

46.2 

4-1 

- .685 









- 3.1 

107 In®. 

47 

03.2 

4-1 

- .681 









- 3.0 

20 Ina. 

47 

39.8 

4-1 

- .673 









— .4 

48 Ina. 

47 

40.8 

4-1 

- .673 









- .8 

97 Ina 

47 

43.6 

4-1 

- .673 









-1.1 

19 In a . 

48 

04.2 

+ 1 

- .668 









-2.5 


48 

14.4 

4-1 

- .666 









-4.0 

14 In a .. 

48 

21.4 

4-1 

— .664 









-2.6 

16 In a 

48 

25.3 

4-1 

- .664 









- .5 

59 In a 

48 

31.3 

4-1 

- .662 









+ .3 


49 

03.9 

4-1 

- .655 









- .2 

1 

49 

07.2 

4-1 

- .654 

+ 0.75 

-2.6 

— 1.3 

OC 

4 

1 

-2.6 


-1.3 


-1.3 


49 

17.6 

4-1 

- .652 







-2.0 


49 

23.0 

4-1 

- .651 









+ .1 

29 In 

49 

35.4 

4-1 

- .648 









- .3 


49 

54.7 

4-1 

- .644 









- .9 

52 Tn a 

50 

04.9 

4-1 

- .642 









-3.9 


50 

34.1 

4-1 

- .635 










70 Tn 

50 

45.8 

4-1 

— .633 









+ 2.5 


50 

51.7 

4-1 

- .631 









-2.9 


50 

51.8 

4-1 

- .631 









- .9 

42 Tn a 

50 

54.1 

4-1 

— .631 









-1.5 

157 

50 

56.8 

4-1 

- .630 

+ .70 

+ 1.5 

+ 2.8 

- .1 

+ 1.5 


+2.8 


+ 2.8 


51 

08.3 

4-1 

— .627 







+2.8 


51 

09.4 

+ 1 

— .627 









+ 1.4 

8 

52 

09.4 

4-1 

— .614 

+ .37 

-4.1 

—3.5 

-5.0 

-4.1 


-3.5 


-3.5 

78 Tn a 

52 

14.2 

4-1 

— .612 









+ 4.2 


52 

27.9 

4-1 

— .609 









+ .7 


52 

35.5 

4-1 

— .608 











53 

02.5 

+1 

— .601 









+ 2.0 

101 Tn a 

53 

23.6 

4-1 

— .596 









+3.9 


53 

24.0 

-j-1 

— .596 









+ *5 

2 

53 

25.6 

-1-1 

— .596 

+ .63 

-3.8 

-2.6 

-5.7 

-3.8 


-2.6 


- 2.6 

32 In « 

53 

29.9 

-f 1 

_ .595 








+ 7.0 

3 a 

53 

52.4 

4-1 

— .590 

+ .53 

—2.8 

—1.8 

-3.8 

-2.8 


-1.8 


- 1.8 


54 

12.2 

4-1 

• 

— .585 









- 5.4 


54 

20. 7 

4-1 

— .583 









- 1.7 

77 In a 

54 

56.8 

4-1 

— .574 









- 1.5 

158 a 

55 

00. 4 

4-1 

— .573 

+ .53 

— .1 

+ -9 

-1.4 

- .1 


+ .9 


+ • 9 

9 

55 

oi.o 

4-1 

4_i 

— .573 

- .09 

+1.2 

+ 1.2 

+ -9 


+ 1.2 


+ 1.2 

+ 1.2 

35 In a 

55 

13.7 

— .570 







- 1.1 


55 

47.1 

28 6 

4-1 

4-1 

— .562 









+ -6 


56 

— .552 









+ 1.9 

88 Tn 

56 

33 i 

4-1 

— . 551 









-3.8 


57 

06 1 

4_ 1 

— .543 









- .5 

159 

57 

13.4 

4-1 

— .541 

+ .56 

— 1.8 

- .7 

-3.0 

-1.8 


- .7 


- .7 

160 

57 

37. 2 

+1 

— .536 

+ .45 

- .3 

+ -6 

-1.5 

- .3 


+ -6 


+ .6 

161 

58 

16. 6 

4-1 

— .526 

+ -41 

+ -5 

+ 1.3 

- .3 

+ .5 


+ 1.3 


+ 1.3 

7 

58 

59 

36.4 
01 8 

4-1 

4-1 

— .521 

4- .20 

- .2 

+ -1 

- .6 

- .2 


+ .1 


4- • 1 


— .515 









-f • 7 


59 

05 5 

4-1 

— .514 









+ 5.8 

4 

59 

59 

27.0 
44 7 

4-1 

4-1 

— .508 

+ .39 

— 1.5 

- .8 

-2.3 

-1.5 


- .8 


- .8 


— .504 









+ 4.4 

5. 

59 

54! 0 

+1 

- .502 

+ .34 

- .i 

+ .5 

- .8 

- .1 


+ -5 


+ .5 


a This station is used only with near-by stations to give a single observation equation. See table of groups on p. 119. 

























































































































































































116 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Observation equations for obtaining corrections to the coefficients of the gravity formula and to the depth of compensation —Con. 


Station number 

Double 

latitude 

24> 

Coefficient of— 

Constant term for solution number— 

X 

y 

z 

1 

2 

3 

4 

5 

6 

7 

8 

62. 

o 

60 

t 

02.6 

+ 1 

-0.499 

+0.39 

— 4.6 

—3.9 

-5.2 


-4.6 


- 3.9 

-3.9 

87 In a. 

60 

24.5 

4-1 

- .494 








- .9 

10 a . 

60 

33.0 

4-1 

— .492 

+ .11 

— .2 

.6 

+ -3 

-0.2 


0.0 


.0 

11 o. 

60 

34.4 

+ 1 

— .491 

+ -11 

.0 

+ -2 

+ .3 

.0 


+ .2 


+ -2 

22 In a. 

60 

39.0 

4-1 

- .490 







- .6 

98. 

60 

43.0 

4-1 

- .489 

+ .85 

— 4.5 

—2.9 

-6.2 


— 4.5 


— 2.9 

-2.9 

89 In a. 

60 

48.4 

4-1 

- .488 








-2.7 

164. 

60 

49.0 

4-1 

- .488 

+ .31 

— .1 

+ -6 

— .8 

- .1 


+ -6 


+ .6 

75 In o. 

60 

55.2 

4-1 

- .486 








-5.5 

71 In. 

61 

19.6 

4-1 

- .480 









-1.9 

92. 

61 

20.4 

4-1 

- .480 

+ -41 

-2.6 

— 1.8 

-3.5 

-2.6 


— 1.8 


-1.8 

93 a. 

61 

38.4 

4-1 

— .475 

+ .28 

+ 3.1 

+ 3.6 

+ 1.8 

+ 3.1 


+3.6 


+ 3.6 

144. 

62 

37.2 

4-1 

- .460 

+ -17 

- .5 

- .2 

-1.1 

- .5 


- .2 


- .2 

64. 

62 

42.6 

4-1 

- .458 

+ .67 

+2.9 

+4.2 

+ -4 


+ 2.9 


+ 4.2 

+ 4.2 

66 In. 

63 

03.2 

4-1 

- .453 




-4.1 

163. 

63 

08.6 

4-1 

- .452 

+ .33 

— 1.6 

-1.0 

— 2.1 

-1.6 


-1.0 


-1.0 

97. 

63 

12.4 

4-1 

- .451 

+ .03 

+ -3 

+ -4 

— .4 

+ -3 


+ -4 


+ -4 

145 a. 

63 

23.0 

4-1 

- .448 

+ .30 

-2.7 

— 2.2 

—3.3 

-2.7 


-2.2 


-2.2 

63. 

63 

32.6 

4-1 

- .446 

+ .19 

— 2.0 

— 1.5 

— 1.6 


-2.0 


— 1.5 

— 1.5 

173. 

63 

38.8 

4-1 

- .444 

-i- .29 

- .2 

+ -3 

-1.3 

— .2 


+ -3 


+ -3 

6. 

64 

56.0 

4-1 

- .424 

+ .12 

-2.7 

— 2.4 

—3.2 

-2.7 


— 2.4 


— 2.4 

61. 

64 

56.8 

4-1 

- .423 

+ .26 

+ 1.7 

+ 2.1 

+ 1.2 


+ 1.7 


+2.1 

+ 2.1 

165. 

65 

17.0 

4-1 

- .418 

+ .45 

+ -9 

+ 1.8 

+ -1 

+ -9 

+ 1.8 

+ 1.8 

65. 

65 

26.6 

4-1 

- .416 

- .13 

-1.6 

-1.7 

— .7 

— 1.6 

— 1.7 

-1.7 

17. 

65 

34.4 

4-1 

- .414 

+ .38 

+ -5 

+ 1.3 

- .3 

+ -5 


+ 1.3 


+ 1.3 

162 a. 

65 

39.6 

4-1 

- .412 

+ .25 

-3.2 

-2.7 

—3.4 

-3.2 


-2.7 


— 2.7 

94. 

66 

15.2 

4-1 

- .403 

+ .06 

+ -7 

+ -9 

+ -1 

+ -7 


+ -9 


+ -9 

142. 

66 

51.0 

4-1 

- .393 

- .06 

-1.9 

-1.9 

-2.0 

— 1.9 


— 1.9 


— 1.9 

174. 

67 

01.6 

4-1 

- .390 

+ .31 

+ 1.9 

+ 2.5 

+ 1.4 

+ 1.9 


+ 2. 5 


+2.5 

167. 

67 

13.0 

4-1 

- .387 

+ .07 

+ -2 

+ .4 

- .1 

+ .2 


+ -4 


+ -4 

15 a. 

67 

30.0 

4-1 

- .383 

+ .24 

+ 1.0 

+ 1.5 

+ -1 

+ 1.0 


+ 1.5 


+ 1.5 

73. 

67 

30.6 

4-1 

- .383 

+ .07 

-1.4 

-1.3 

-1.2 

-1.4 


— 1.3 


— 1.3 

66. 

67 

46.8 

4-1 

- .378 

+ .19 

+ 3.8 

+ 4.2 

+ 4.2 


+3.8 


+ 4.2 

+ 4.2 

16. 

67 

49.6 

4-1 

- .377 

+ .13 

-2.7 

-2.3 

-3.5 

— 2.7 

—2.3 

—2.3 

149. 

68 

28.4 

4-1 

- .367 

+ .55 

+ 1.3 

+ 2.3 

.0 

+ 1.3 


+2.3 


+2.3 

99. 

68 

46.4 

+1 

- .362 

+ .31 

+ -2 

+ .8 

— .3 

+ .2 

+ .8 

+ .8 

143<». 

69 

00.2 

4-1 

- .358 

-i- .07 

-2.8 

—2.6 

— 3.0 

—2. 8 

—2.6 

— 2.6 

96o. 

69 

10.4 

4-1 

- .356 

+ .16 

+ 4.1 

+4.4 

+ 2.9 

+ 4.1 


+ 4. 4 


+ 4. 4 

150. 

69 

24.0 

4-1 

- .352 

+ .28 

-1.6 

— 1.0 

— 2.3 

— 1.6 


— 1.0 


1.0 

18. 

69 

26.2 

4-1 

- .351 

+ .85 

- .3 

+ 1.3 

— 2.3 

— .3 


+ 1.3 


+ 1.3 

166». 

69 

27.6 

4-1 

- .351 

+ .27 

+ 1.0 

+ 1.5 

+ 1.2 

+ 1.0 


+ 1. 5 


+1.5 

13 a. 

69 

30.0 

4-1 

- .350 

- .06 

-3. 7 

—3.8 

— 3.9 

—3. 7 


—3.8 


3. 8 

12. 

69 

52.4 

4-1 

- .344 

- .02 

+ 1.8 

+ 1.9 

+ 1.8 

+ 1.8 


+ 1.9 


+ 1. 9 

168. 

70 

17.6 

4-1 

- .337 

+ .OS 

-2.2 

-2.1 

- 2.3 

—2.2 


— 2.1 


— 2.1 

153. 

70 

18.8 

4-1 

- .337 

+ .37 

+ .9 

+ 1.5 

+ 1.3 

+ .9 


+ 1.5 


+ 1. 5 

72. 

70 

25.6 

4-1 

- .335 

+ . 19 

-4. 4 

— 4.0 

— 4.7 

—4. 4 

-4.0 

4 0 

151a. 

70 

27.6 

4-1 

- .334 

+ .29 

-4.0 

-3.3 

— 4.8 

— 4. 0 


—3. 3 

£3 

141 a. 

70 

46.6 

+ 1 

- .329 

- .05 

+ .8 

+ .8 

+ 1.5 

+ .8 


+ .8 


+ .8 

70. 

71 

03.6 

4-1 

- .325 

+ .76 

-1.0 

+ .5 

— . 9 

— 1. 0 

4- 5 

4- 5 

71. 

71 

11.6 

4-1 

- .322 

+ .82 

-2.7 

— 1.1 

— 2.8 


— 2. 7 


1 1 

1.1 

152. 

71 

11.8 

4-1 

- .322 

+ .89 

-2.0 

- .3 

-2.9 

—2.0 


— .3 


— .3 

14 a. 

71 

13.4 

4-1 

- .322 

+ .06 

-3.8 

-3.4 

— 4.0 

—3.8 


—3. 4 


—3. 4 

148. 

71 

13.6 

4-1 

- .322 

+ .44 

+ . 1 

+ 1.0 

— . 9 

+ . 1 


+ 1.0 


4-1. 0 

155 a. 

71 

55.4 

4-1 

- .310 

+ .25 

+ .8 

+ 1.3 

+ 1. 4 

+ .8 


+ 1.3 


4-1 3 

91. 

72 

00.4 

4-1 

- .309 

+ .23 

-4.9 

-4. 4 

— 5.8 

— 4.9 


— 4. 4 


4, 4 

68 a. 

72 

07.8 

4-1 

- .307 

+ .73 

-2.3 

— .9 

— 4.3 


—2. 3 


9 

^9 

69 a. 

72 

10.6 

4-1 

- .306 

-i- .56 

-1.0 

+ .2 

+ 9.8 


— 1. 0 


+ I 2 

4- 2 

154 a. 

72 

12.2 

4-1 

- .306 

+ .43 

+2.3 

+3.0 

+ 1.8 

+ 2. 3 


+3. 0 

+3 0 

102 a. 

72 

12.4 

4-1 

- .306 

+ 1.15 

-3.3 

-1.2 

— 14. 2 

—3.3 


— 1. 2 


l’ 2 

103 a. 

72 

17.0 

4-1 

- .304 

+ 1.10 

+ .1 

+2.1 

— 3.2 

+ • 1 


+2.1 


4-2 1 

101 a. 

72 

51.8 

4-1 

- .295 

+ .41 

-5.6 

— 4.8 

— 6.3 

—5.6 


4. 8 


4 8 

169. 


72 

58.6 

4-1 

- .293 

+ -11 

-2.3 

—2.1 

— 1.9 

— 2. 3 


2.1 


2.1 

156o. 

73 

10.8 

4-1 

- .289 

+ .58 

- .4 

+ .7 

— . 5 

— .4 


+ 7 


4- 7 

95. 

73 

11.0 

4-1 

- .289 

- .10 

- .8 

- .9 

— 1.0 

— . 8 


. 9 


9 

147«. 

73 

20.4 

4-1 

- .287 

+ .30 

—2. 7 

-2.1 

— 3.6 

—2.7 


-2.1 


2.1 

100. 

73 

21.4 

4-1 

- .286 

+ .08 

+ .6 

+ .9 

+ 1.0 


+ .6 

+ .9 

4- Q 

90. 

73 

41.0 

4-1 

- .281 

+ .61 

+2.8 

+4. 0 

+ 1.5 

+2.8 

4-4 O 

+4 0 

170. 

73 

43.2 

4-1 

- .280 

+ . 12 

-1.7 

-1.4 

— 2.0 

— 1.7 


1 4 


1 4 

140. 

74 

10.8 

4-1 

- .273 

+ .12 

-2.6 

—2.4 

— 2.5 

—2.6 


-2.4 


2 4 

55 a. 

74 

40.8 

4-1 

- .264 

+ 1.15 

—2.5 

— .5 

— 12.5 


-2.5 


5 

146o. 

75 

04.4 

4-1 

- .258 

+ .22 

-1.6 

-1.1 

— 2.1 

— 1.6 

i i 


i'i 

171. 

75 

17.8 

4-1 

- .254 

+ .30 

+ 1.5 

+ 2.2 

+ 1.0 

+ 1.5 


+2 2 


+2 2 

176. 

75 

21.2 

4-1 

- .253 

+ .22 

+ 1.1 

+ 1.6 

+ 2.0 

+ 1.1 


4-1 ft 


4-1 fi 

139. 

75 

22.2 

4-1 

- .253 

+ .23 

-2.3 

— 1. 9 

— 3.1 

-2.3 


-1.9 


1 9 

67. 

75 

24.4 

4-1 

- .252 

+ .78 

— 1.0 

+ .5 

— 2.2 

- 1.0 

4 - K 

4 -~ £ 

175 a . 

75 

34.4 

4-1 

- .249 

+ .42 

+ .8 

+ 1.6 

+1.1 

+ .8 

+ 1.6 


4-1 ft 

54 a. 

75 

35.0 

4-1 

- .249 

+ .89 

- .1 

+ 1.5 

— 3.0 

— . 1 

+1.5 

4-15 

172 a . 

75 

38.2 

4-1 

- .248 

+ .59 

+ 1.6 

+2.6 

+ 2.9 

+ 1.6 


+2 6 

+2 6 

215 . 

75 

57.6 

+1 

- .243 

+ .43 

+ 1.2 

+2.1 

+ .2 

+ 1.2 


+211 


+ 2il 


“ This station is used only with near-by stations to give a single observation equation. See table of groups on p. 119. 




































































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 117 

Observation equations for obtaining coirections to the coefficients of the gravity formula and to the depth of compensation —Con. 


Station number 


19.. . 

216.. 
104 a. 
25M. 

45.. . 

38.. . 

40.. . 
214®. 
213 a. 
43 a.. 
42a.. 
21a.. 
22 a.. 

41.. . 
84®.. 
47®.. 


46.. .. 
212 a. 

39.. . 
209 a. 

34.. . 

217.. . 

116.. . 
135 a. 

23 a.. 

114.. . 
125 a. 

20 .. . 

35.. . 
219 a. 
44 a.. 

137.. 

138.. 
48 a.. 

24 a.. 

136.. 


207 a. 

210 a. 

25 a.. 

211 a. 

26 a.. 
208.. 

49 .. . 

105.. 

27 a.. 

126.. 
115.. 


120 .. 

83.. . 

81.. . 

124.. 

33.. . 

82.. . 

122 .. 

127.. 

36.. . 
37M. 


133 a. 

134 b. 

117.. 

28 a.. 

18C.. 

29 a.. 

30 a.. 

205.. 
32a.. 

119.. 
123 a. 

195.. . 

206.. 

121 ... 


131 . 

37 . 

17 C a. 

204. 

198®. 

88 c. 

130®. 

79. 

60. 

38 M... 

25 C. 

16 C a. 

132 d . 

197. 


Double 

latitude 

2* 


76 

76 

76 

76 

77 
77 
77 
77 
77 
77 
77 
77 
77 
77 
77 

77 

78 
78 
78 
78 
78 
78 
78 
78 
78 
78 
78 
78 

78 

79 
79 
79 
79 
79 
79 

79 

80 
80 
80 
80 

81 

81 

81 

81 

81 

81 

81 

82 

82 

82 

82 

83 

83 

83 

83 

83 

83 

84 
84 
84 
84 
84 
84 
84 
84 

84 

85 
85 
85 
85 

85 

86 
86 
86 
86 
86 
86 
87 
87 
87 
87 
87 
87 
87 

5 87 


04.0 

36.2 

41.8 

54.6 
05.2 
16.0 

27.4 

35.4 
38.0 

40.6 

41.4 

46.4 

46.6 

49.4 

52.6 

55.8 

08.4 

09.8 

11.6 
12.6 
16.6 

19.4 

29.8 
32.0 

35.6 

39.2 

43.8 
50.0 

57.4 
17.0 

21.2 

31.8 

35.4 

41.6 

54.2 

55.6 

08.0 

32.0 

42.0 

54.8 
28.0 

29.2 

32.2 

35.8 
37.0 
52.0 

56.8 

12.8 

14.8 

36.6 

44.8 

00.8 

10.2 

15.4 

21.4 

34.8 
47.0 

07.4 

15.6 

32.2 
33.0 

38.5 

43.2 

45.6 
46.0 

54.2 

01.6 

18.2 
40.0 

44.6 
56.0 

05.4 

09.2 

17.1 

33.6 

35.4 

36.8 
06.0 

14.4 

23.6 

30.4 

40.2 

45.4 

56.6 

57.2 


Coefficient of— 


+1 
+1 
+1 
+ 1 
+1 
+1 
+ 1 
+ 1 
+1 
+1 
+ 1 
+ 1 
+ 1 
+1 
+1 
+1 

+1 
+1 
+ 1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 
+1 
+ 1 
+1 
+1 
+1 
+ 1 
+1 
+1 
+ 1 
+1 
+1 
+1 
+1 

+ 1 
+ 1 
+ 1 
+ 1 
+ 1 
+ 1 
+ 1 
+1 
+ 1 
+ 1 
+ 1 
+ 1 
+1 
+1 


Constant term for solution number— 


- 2. 

l! 
5. 
2. 


y 

z 

1 

2 

3 

-0.241 

+0.18 

+ 0.1 

+ 0.5 

+ 

- .232 

+ .20 

-1.7 

-1.3 

— 

- .230 

+ .03 

+ 1.4 

+ 1.6 

4* 

- .226 





- .223 

+ .90 

-4.8 

-2.8 


- .220 

- .03 

- .3 

- .3 

— 

- .217 

- .02 

-2.2 

-2.2 

— 

- .215 

+ .21 

-4.8 

-4.4 


- .214 

+ .20 

-2.6 

-2.1 

— 

- .213 

+ 1.61 

-5.7 

-2.9 

-2 

- .213 

+ .66 

-1.4 

- .1 

+ 

- .212 

+ .13 

-4.8 

-4.5 


- .212 

+ .13 

-5.0 

-4.7 


- .211 

+ .25 

- .2 

+ .4 

+ 

- .210 

+ .13 

-4.9 

-4.5 


- .208 

- .34 

+ 1.6 

+ 1.3 

+ 

- .206 

- .06 

-3.4 

-3.2 

+ 

- .205 

+ .23 

-5.9 

-5.4 

— 

- .205 

- .05 

+ .8 

+ -8 

+ 

- .204 

+ .23 

-4.7 

-4.2 

— 

- .203 

+ .03 

+ .9 

+ 1.1 

+ 

- .202 

+ .28 

- .5 

+ . 2 

— 

- .199 

+1.10 

- .8 

+ 1.3 

— 

- .199 

+ .13 

+ 1.3 

+1.6 

+ 

- .198 

+ .20 

- .2 

+ -3 

— 

- .197 

+ 1.75 

-1.2 

+2.0 

— 

- .195 

+ .42 

■f- • 7 

+ 1.5 

— 

- .194 

+ .82 

-3.3 

-1.8 

— 

- .192 

- .01 

.0 

+ .1 


- .186 

+ .27 

+3.5 

+4.1 

+ 

- .185 

- .07 

+ .6 

+ .8 

+ 

- .182 

+ .17 

-1.2 

- .9 

— 

- .181 

+ .03 

+ • 7 

+ -8 

+ 

- .179 

+ 1.00 

-3.2 

-1.2 

— 

- .175 

+ .19 

-3.5 

-3.0 

— 

- .175 

+ .12 

+ .1 

+ .4 

+ 

- .171 

+ .20 

+1.6 

+2.1 

+ 

- .164 

+ .22 

+ 1.6 

+2.1 

+ 

- .162 

+ .19 

+ -6 

+ 1.1 


- .158 

+ .22 

+ 1.1 

+ 1.5 

+ 

- .148 

+ .23 

-3.8 

-3.2 


- .148 

+ .13 

- .2 

.0 

— 

- .147 

+ .06 

-2.1 

-1.8 

+ 

- .146 

+ .30 

+ • 6 

+ 1.3 

+ 

- .146 

+ .24 

-3.6 

-3.0 


- .141 

+ .41 

+ .5 

+ 1.4 

— 

- .140 

+ .13 

- .4 

+ .1 

+ 

- .135 

+ .14 

- .2 

.0 

+ 

- .135 

+ .09 

- .5 

- .2 

— 

- .129 

+ 1.15 

-2.1 

4* • 2 


- .126 

+ .40 

+ 1.6 

+2.5 

+ 

- .122 

+ .OS 

- .7 

— .5 

— 

- .119 

+ .44 

-3.1 

-2.1 

— 

- .117 

+ .12 

-2.2 

-1.9 

— 

- .116 

+ .50 

- .4 

+ -6 

— 

- .112 

- .10 

- .1 

- .1 

— 

- .102 

+ .44 

+ 1.3 

+2.2 

+ 

- .100 

+ .07 

+ 1.7 

+ 1.9 

+ 

- .095 

- .11 

-4.5 

—4.4 

— 

- .095 

+ .38 

+ .4 

+ 1.2 

—* 

0Q3 



—2.0 

— 

_ ! 092 

+ .28 

-1.9 

-1.3 

— 

_ .091 

+ .33 

-2.0 

-1.3 

— 

— .091 

- .03 

-1.0 

-1.0 

— 

- .089 

+ .21 

+ 1.0 

+ 1.5 

+ 

- .087 

- .03 

-2.3 

-2.3 

— 

- .082 

+ .15 

+3.1 

+3.5 

+ 

— .076 

+ .34 

-3.5 

-2.7 

+ 

- .074 

+ -14 

-3.0 

-2.6 

— 

- .071 

+ .08 

-1.2 

-1.0 


- .068 

+ .35 

+ 1.0 

+ 1.6 

+ 

- .067 

+ .08 

- .5 

- .3 

— 

065 



4" • ^ 

+ 

- !o60 

+ -17 

+ 1.5 

+1.8 

+ 

- .059 

+ .07 

-6.4 

-6.2 

— 

— .059 

- .10 

+ .3 

+ .2 

+ 

- .051 

i+ .14 

+2.7 

+3.1 

+ 

- .048 

- .34 

-1.2 

—1.6 

+ 

- .045 

- .07 

- .7 

— .9 


— .044 
041 



-1.9 

— 

039 



+2.6 

+ 

- !036 

+ -11 

+ 1.4 

+ 1.7 

+ 

- .036 

+ .02 

-1.5 

— 1.4 



0.3 


6.7 
.9 

4.9 
.9 

1.1 

.7 

2.2 

.3 

3.7 
.3 

5.9 
.0 

3.5 

2.3 

1.2 

.3 

3.6 

3.9 
.3 

2.4 

1.9 
.2 

1.5 
4.0 

.7 

2.3 
.3 

4.1 
.6 
.5 

.3 

.4 

1.3 

2.2 

.5 

2.0 

3.0 

1.8 

.8 


1.8 

1.8 

2.8 

.6 

2.0 

2.6 

2.3 

1.5 
1.0 

2.5 
4.1 

.1 

3.0 

1.3 


.6 

1.1 


2.6 

.3 


3.0 

1.6 


+0.1 
-1.7 
+ 1.4 


- .3 


-4.8 

- 2.6 


-4.8 

-5.0 


-4.9 


-5.9 
+ .8 
-4.7 
+ -9 
- .5 


+ 1.3 
- .2 


+ • 7 
-3.3 
.0 
+3.5 


- 1.2 
+ .7 


-3.5 

+ .1 

+ 1.6 
+ 1.6 
+ .6 
+ 1.1 
-3.8 
- .2 


+ • 0 
-3.6 
+ -5 


- .2 


+ 1.6 

- .7 


- 2.2 

- .4 

- .1 


+ 1.3 
+ 1.7 


+ .4 


-1.9 
- 2.0 
- 1.0 
+ 1.0 
-2.3 
+3.1 


- 1.2 

+ 1.0 

- .5 


+ 1.5 


+ .3 
+2.7 


+ 1.4 
-1.5 


-4.8 


- 2.2 


-5.7 

-1.4 


- .2 
'+i.‘6' 

-3.4 


- .8 


- 1.2 


+ .6 
—3.2 


- 2.1 


- .4 


- .5 
- 2.1 


- 3.1 


-4.5 


- 3.5 

- 3.0 


-6.4 


- 1.2 
- .7 


+ 0.5 
- 1.3 
+ 1.6 


- .3 


-4.4 

- 2.1 


-4.5 

-4.7 


-4.5 


-5.4 
+ .8 
-4.2 
+ 1.1 
+ .2 


+1.6 

+ -3 


+ 1.5 
- 1.8 
+ .1 
+4.1 


- .9 
+ .8 


- 3.0 
+ .4 

+2.1 
+2.1 
+ 1.1 
+ 1.5 
- 3.2 
.0 


+ 1.3 
- 3.0 
+ 1.4 


+ 2.5 
- .5 


- 1.9 
+ .6 
- .1 


+2.2 

+ 1.9 


+1.2 
-2.0 
- 1.3 
- 1.3 
-1.0 
+ 1.5 
- 2.3 
+ 3.5 


-1.0 

+1.6 
- .3 
+ . 4 
+ 1.8 


+ • 2 
+ 3.1 


- 1.9 
+2.6 
+ 1.7 
- 1.4 


- 2.8 


- 2.2 


- 2.9 
- .1 


+ .4 
+i.’3' 
-3.2 


+ 1.3 


+2.0 


+ .8 

-i.2 


- 1.8 


+ .1 


- .2 
+ .2 


- 2.1 


-4.4 


- 2.7 

- 2.6 


- 6.2 


- 1.6 
- .9 


« This station is used only with n«t-by oWio™ » JS^tllXSSt ft * 

i US SS&SSLSiS fiS 5 ,. 1 .CVJ & «»J 8 «»pm »t gr.« P * c, P . m 


+ 0.5 

- 1.3 

+ 1.6 

+6.6 

- 2.8 

- .3 
- 2.2 
- 4.4 
- 2.1 
- 2.9 

- .1 
- 4.5 
- 4.7 
+ .4 
- 4.5 
+ 1.3 

- 3.2 
- 5.4 
+ .8 
- 4.2 
+ 1.1 
+ .2 
+ 1.3 
+ 1.6 
+ .3 
+ 2.0 
+ 1.5 
- 1.8 
+ .1 
+ 4.1 
+ .8 

- .9 
+ .8 
- 1.2 
- 3.0 
+ .4 

+ 2.1 
+ 2.1 
+ 1.1 
+ 1.5 
- 3.2 
.0 

- 1.8 
+ 1.3 
- 3.0 
+ 1.4 
+ .1 

.0 

- .2 
+ .2 
+ 2.5 

- .5 
- 2.1 
- 1.9 
+ .6 

- .1 
- 5.9 

+ 2.2 
+ 1.9 
- 4.4 
+ 1.2 
- 2.0 
- 1.3 
- 1.3 
- 1.0 
+ 1.5 
- 2.3 
+ 3.5 
- 2.7 
- 2.6 
- 1.0 

+ 1.6 

- .3 
+ • 4 
+ 1.8 
- 6.2 
+ .2 
+ 3.1 
- 1.6 

- .9 
- 6.8 
- 1.9 
+ 2.6 
+ 1.7 
- 1.4 























































































































































































































































































118 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Observation equations for obtaining corrections to the coefficients of the gravity formula and to the depth of compensation —Con. 


Station number 

Double 

latitude 

20 

Coefficient of— 

Constant term for solution number— 

X 

V 

z 

1 

2 

3 

4 

5 

6 

7 

8 

181. 

o 

88 

/ 

06.4 

+ 1 

-0.033 

- 40.02 

-2.5 

-2.3 

- 1.7 

-2.5 


-2.3 


-2.3 

201 a. 

88 

08.4 

+ 1 

- .032 

— .17 

-3.6 

-3.8 

- 2.5 


-3.6 


-3.8 

—3.8 

128. 

88 

12.6 

+1 

- .031 

4 .27 

4 .2 

+ .7 

- .4 

. 

+ .2 


+ .7 


+ .7 

3 Ca. 

88 

29.2 

+1 

- .026 


+ .4 

- .4 



+ .4 


+ .4 

202 . 

88 

31.0 

+1 

- .026 

4 .19 

-3.4 

-2.9 

-3.4 


-3.4 


-2.9 

—2.9 

86 a. 

88 

35.0 

+ 1 

- .025 

+ .72 

-2.7 

-1.4 

- 4.6 

-2.7 


-1.4 


— 1.4 

196. 

88 

35.6 

+1 

- .025 

4 .08 

-4.5 

-4.4 

-4.4 

-4.5 


-4.4 


—4. 4 

75 a. 

88 

42.2 

-f 1 

— .023 

4 .73 

-7.3 

- 6.0 

— 10.4 


-7.3 


- 6.0 

— 6.0 

118. 

88 

43.8 

+ 1 

- .022 

- .19 

— 1.9 

- 2.2 

- .9 


-1.9 


- 2.2 

— 2.2 

180. 

88 

47.2 

+1 

- .021 

+ .12 

43.2 

+3.4 

+ 2.9 

+3.2 


+3.4 


+3.4 

40 M. 

88 

58.4 

+ 1 

- .018 



—4.7 

129. 

88 

59.0 

+ 1 

- .018 

4 .52 

.0 

+ 1.0 

+ -3 

.0 


+ 1.0 


+ 1.0 

52 a. 

89 

06.8 

4-1 

— .015 

4 .95 

—2 6 

- .7 

- 3.5 


- 2.6 

- .7 

— .7 

87 6 . 

89 

20.2 

4-1 

— .012 

-i- .07 

-3.1 

-2.9 

- 2.5 

-3.1 


-2.9 


—2.9 

24 C a. 

89 

21.6 

4-1 

- .011 


+ 2.1 

+ 1.3 



+ 2.1 


+ 2.1 

50a. 

89 

26.6 

4-1 

— .010 

41.21 

-2.9 

- .6 

- 4.4 


-2.9 

- .6 

— .6 

51a. 

89 

28.4 

4-1 

— .009 

41.05 

-4.9 

-2.9 

- 6.0 


-4.9 


-2.9 

—2.9 

177. 

89 

31.6 

4-1 

- .008 

.00 

- 1.0 

- .9 

- 1.1 

- 1.0 


- .9 


- .9 

109. 

89 

36.0 

4-1 

- .007 

4 .18 

-4.5 

-4.0 

- .9 


-4.5 


-4.0 

—4.0 

85 a. 

89 

38.2 

4-1 

- .006 

- .09 

- .8 

- .9 

.0 

- .8 


- .9 


— 9 

179. 

89 

46.4 

4-1 

- .004 

4 .01 

+ 1.7 

+ 1.7 

+ 1.8 

+ 1.7 


+ 1.7 


+ 1.7 

199. 

89 

51.6 

4-1 

— .002 

- .02 

—2.5 

-2.5 

- 2.2 

—2.5 


-2.5 


—2.5 

182 a. 

89 

55.6 

4-1 

— .001 

4 .08 

44.1 

+4.2 

+ 3.6 

+4.1 


+4.2 


+4.2 

74 a. 

89 

57.4 

4-1 

— .001 

- .07 

-6.7 

-6.7 

- 6.2 

-6.7 


-6.7 


—6.7 

187 a. 

90 

02.6 

4-1 

4 .001 

4 .08 

-2.4 

-2.3 

- 2.9 


-2.4 


-2.3 

—2. 3 

89. 

90 

07.6 

4-1 

4- .002 

4 .07 

4 .9 

+ 1.2 

+ 1.2 

+ .9 


+ 1.2 


+ 1.2 

200 . 

90 

09.0 

4-1 

4 .003 

+ .02 

-1.5 

-1.4 

- 1.7 

-1.5 


-1.4 


— 1. 4 

31. 

90 

22.4 

+ 1 

4 .007 

4 .22 

— .4 

.0 

- 1.0 

- .4 


.0 


o 

19 C. 

90 

32.1 

4-1 

4 .009 



— 1.4 

- 3.0 



-1.4 


— 1 4 

15 C. 

90 

38.1 

4-1 

4 .011 



-1.4 

- 1.5 



-1.4 


— 1 4 

113. 

90 

42.8 

4-1 

4 .012 

- .08 

42.0 

41.9 

+ 2.6 


+ 2.0 


+1.9 

+ 1 9 

23 C a. 

90 

43.3 

4-1 

4 .013 


- .2 

— 1.6 


- .2 

— 2 

1 Ca. 

90 

47.3 

-j -1 

4 .014 



41.0 

+ 1.0 



+ 1.0 


+ 1 o 

8 Ca. 

90 

48.9 

4-1 

4 .014 



-1.4 

— ]. 7 



-1.4 


— 1 4 

186. 

90 

55.0 

4-1 

4 .016 

- .09 

-1.9 

- 2.0 

- 1.5 


-1.9 


- 2.0 

— 2 0 

183 a. 

91 

04.8 

4-1 

-i- .019 

4 .12 

43.8 

44.1 

+ 3.3 

43.8 


+ 4.1 

+ 4 1 

107. 

91 

05.2 

-j-l 

4 .019 

4 .27 

-3.7 

-3.2 

-4.2 

-3.7 


-3.2 


—3^2 

184 a. 

91 

08.0 

4-1 

4 .020 

4- .05 

+ 1.8 

41.9 

+ 1.7 

+ 1.8 


+ 1.9 


4-1 Q 

7 Ca. 

91 

33.1 

4-1 

4 .027 

-1.9 

- 2.5 


-1.9 


— 1 9 

33 Ma. 

91 

44.2 

4-1 

4 .030 









— 1 n 

194. 

91 

48.0 

4-1 

4 .031 

- .23 

-1.7 

-1.9 

+ .3 


-1.7 


-1.9 

— 1 9 

35 M a. 

91 

52.6 

4-1 

4 .033 









— 4 5 

11 Ma. 

91 

58.0 

4-1 

4 .034 









—5 3 

36 M a. 

91 

59.0 

4-1 

4 .035 









—5 7 

12 Ma. 

91 

59.2 

+ 1 

4 .035 









— 5 5 

13 M a. 

92 

03.0 

4-1 

4 .036 









—4 4 

20 C. 

92 

10.1 

4-1 

4 .038 



— .2 

— 1.6 



— .2 


12 

57 . 

92 

10.8 

4-1 

4 .038 

4 .32 

-5.2 

— 4.6 

— 6.0 

-5.2 


—4.6 


4 6 

22 C . 

92 

16.7 

4-1 

4 .040 


-f .1 

— 1.3 


+ . 1 


+ 1 

26 C. 

92 

18.1 

4-1 

4 .040 



+ 1.5 

+ .7 



+1.5 


4-1 R 

80. 

92 

22.6 

4-1 

4 .041 

4 .30 

— .1 

+ .5 

— .3 


- .1 

+ .5 

4- 5 

30 M a. 

92 

25.0 

4-1 

4 .042 






4 

18 M a. 

92 

26.0 

4-1 

4 .042 









— 7 

21 C . 

92 

27.8 

4-1 

4 .043 



+ 

00 

— .5 



+ .8 


4- 8 

28 M a. 

92 

28.2 

-i -1 

-i- .043 







4- 7 

110 . 

92 

28.4 

4-1 

4 .043 

4 .56 

— .5 

4 .7 

+1.4 


— .5 


+ .7 

4- 7 

32 M a . 

92 

29.8 

4-1 

4 .044 







1 4 

108. 

92 

34.4 

4-1 

+ .045 

- .04 

— .2 

— .2 

— .3 

— .2 


— . 2 


9 

29 M a. 

92 

35.2 

4-1 

4 .045 









4- 9 

188. 

92 

36.8 

4-1 

4 .046 

+ .13 

-4.6 

— 4.3 

— 4.1 


-4.6 


-4.3 

4 3 

9 C. 

92 

37.4 

4-1 

+ .046 

+ 2.2 

+3.5 


+ 2.2 

_L9 9 

34 M a. 

92 

38.6 

4-1 

+ .046 






9 n 

15 M a. 

92 

39.4 

-fl 

4 .046 









4- 4 

178. 

92 

41.6 

-i-i 

4 .047 

4 .14 

- 1.2 

- .9 

— 1 . 6 

— 1 . 2 


— 9 


9 

185. 

92 

42.6 

4-1 

4 .047 

+ .06 

— 2.2 

— 2.0 

—2.3 

- 2.2 


— 2 *. 0 


9 0 

2 C. 

92 

44.9 

41 

4 .048 


+ .2 

+ .3 


+ 2 


4- 9 

14 M a. 

92 

45.8 

41 

4 .048 







1 0 

31 M a. 

92 

46.4 

41 

4 .048 









2 1 

8 M a. 

92 

48.2 

41 

4 .049 









1 9 

193. 

92 

48.4 

4-1 

4 .049 

—.06 

-3.8 

-3.8 

- 1.8 


-3.8 


-3.8 

9 « 

17 M a. 

92 

48.4 

41 

+ .049 





0 

16 M a. 

92 

50.4 

41 

4 .050 









1 3 

7 M a. 

92 

52.0 

41 

4 .050 









2 6 

12 C. 

93 

00.9 

4-1 

4 .053 



+1.3 

+ 1.8 



+1.3 


j-1 3 

1 M a. 

93 

03.6 


4 .053 






4-1 n 

2 M a. 

93 

04.0 

41 

4 .054 









4-1 4 

6 C. 

93 

25.1 

41 

+ .060 



— .3 

— . 8 



— . 3 


Q 

203. 

93 

34.0 

41 

4 - .062 

+ .01 

-5.9 

—5. 8 

— 4.8 

-5.9 


-5.8 


r. 0 

76 . 

93 

37.0 

41 

4- .063 

- .02 

-1.0 

-1.0 

- .5 

-1.0 

-1.0 

-1.0 


a This station is used only with near-by stations to give a single observation equation. See table of groups on p. 119. 
b Station 87 enters solutions 1 and 4 as a part of group 3; solutions 2, 3, 6, and 8 as a part of group 9 C, p. 120. 
































































































































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 119 

Observation equations for obtaining corrections to the coefficients of the gravity formula and to the depth of compensation —Con. 


Station number 

Double 

latitude 

20 

Coefficient of— 

Constant term for solution number— 

X 

y 

z 

1 

2 

3 

4 

5 

6 

7 

8 

10 M a . 

O 

94 

9 

00.2 

+1 

4-0.070 









—3.2 

9 M a . 

94 

02.8 

+1 

+ .071 









—4 4 

112 . 

94 

06.8 

+1 

4- .072 

— .15 

-3.9 

— 4.1 

— 2 9 


-3.9 


-4.1 

—4 1 

106 b. 

94 

29.8 

+1 

4 - .078 

.00 

4- .4 

+ .5 

4 - 4 

+ .4 

4- 5 

4- F 

218. 

94 

31.6 

+1 

4- .079 



—3.9 

— 5 9 


—3 9 


_3 .9 

27 C a . 

94 

44.0 

+1 

4- .083 



-f .3 

4- 1 3 



4- 2 


4- 3 

10 C. 

95 

01.1 

+1 

4- .087 



— .6 

— 2 



— 6 


— 6 

28 C. 

95 

14.3 

+1 

4- .091 



4 - 1 . 8 

4 - 1.8 



+ 1.8 


4 - 1*8 

Ill. 

95 

24.8 

+ 1 

4- .094 

4- .62 

4- .8 

4-2.0 

+ 67 


+ .8 

+ 2.0 

4-2 0 

191. 

95 

32.4 

4-1 

4 - .097 

— .09 

— 1 . 8 

— 1.9 

— 1 3 

—i 8 

1 9 

—19 

58. 

95 

37.2 

4-1 

4- .098 

4- .22 

-3.4 

—3.1 

— 3 9 

-3.4 


3 1 


—3 1 

13 C. 

95 

40.9 

4-1 

4- .099 

— 1 . 2 

— 2. 4 


- 1.2 


—l’ 2 

192. 

96 

13.6 

4-1 

4- .108 

- .07 

-2.5 

—2 7 

— 1 8 


-2.5 

-2.7 

_ 2 .7 

5 C. 

96 

16.8 

4-1 

4- .109 

— 9 

— .5 


- .9 

— 9 

78. 

96 

32.8 

4-1 

4- .114 

— . 12 

— 1.6 

— 1.0 

4-3 4 


—1 0 

—1 0 

— 10 

189. 

96 

40.6 

4-1 

4- .116 

— .04 

—4.0 

—4.0 

— 3 6 


4 0 


— 4 O 

—4 0 

77. 

96 

47.6 

-j -1 

4- .118 

— .14 

—3. 4 

—3.7 

— 2.0 


-3.4 


-3.7 

—3 7 

14 C. 

96 

52.0 

4-1 

4- .120 



4-3. 7 

4-5.1 


4-3 7 

4-3 7 

4 C. 

97 

01.8 

4-1 

4- .122 



4-2.0 

4-3.5 



-j -2 0 


4-2 0 

29 C. 

97 

03.1 

4-1 

4- .123 



— 1.6 

— 1.4 



- 1.6 


— 1 6 

190. 

97 

49.4 

4-1 

4- .136 

.00 

—2. 5 

—2.5 

— 2.6 


-2.5 

-2.5 

_2. 5 

59. 

97 

56.2 

4-1 

4- .138 

- .13 

-2.5 

—2.7 

— 1 8 

-2.5 

_ 2 .7 

—% 7 

11 C. 

98 

07.5 

4-1 

4- .141 

4-1. 4 

4 - 1.8 


+1.4 


4-1.4 

42 C. 

98 

33.6 

4-1 

4- .149 



4- .8 

4-5.4 



+ .8 

4- .8 

30 C. 

99 

32.0 

4-1 

4 - .166 



— .9 

— 2.7 



- .9 

— .9 

32 C. 

99 

41.8 

4-1 

4- .168 



— 1.5 

— 1.3 



— 1 5 

— 1.5 

40 C. 

99 

44.6 

4-1 

4- .169 



.0 

4 - 12.2 




.0 

.0 

31 C . 

99 

48.8 

4-1 

4- .170 



4- . 1 

— . 1 



+ .1 

4- - 1 

34 C. 

100 

04.8 

4-1 

4- .175 



— .2 

.0 



— .2 

— .2 

33 C. 

100 

46.9 

4-1 

4- .187 



- .3 

— . 6 




— .3 

— .3 

39 C. 

101 

21.4 

4-1 

4- .197 



+ .1 

4- 7.4 




+ .i 

4- .1 

3 M a . 

101 

28.4 

4-1 

4- .199 






—2.9 

4 M a . 

101 

31.4 

4-1 

4- .200 









— 1.9 

38 C a . 

101 

59.6 

4-1 

4 - .208 



4-3.5 

4-11.5 




4-3.5 

4-3 5 

35 C. 

102 

05.4 

4-1 

4 - .209 

« 


— .4 

+ 1.8 




— .4 

— .4 

36 C a . 

102 

21.8 

4-1 

4- .214 



— 1.5 

— .3 




—1.5 

— 1.5 

41 C a . 

102 

31.5 

4-1 

4- .217 



— 1.0 

4-5.6 




— 1.0 

—1.0 

37 C o . 

102 

47.4 

4-1 

4- .221 



4- .3 

+ 6.3 




+ .3 

4- .3 


103 

36.0 

4-1 

4- .235 







—5.3 

6 M a . 

103 

40.0 

+ 1 

4- .236 









-5.2 













a This station is used only with near-by stations to give a single observation equation. See table of groups below. 
6 Station 106 enters alone only in solutions 1 and 4; as a part of group 3 C, p. 120, in solutions 2, 3, 6, and 8. 


ARRANGEMENT OF GROUPS. 


Group 

number 

Including stations 

Coefficient of— 

Constant term for solution number— 

X 

V 

z 

1 

2 

3 

4 

5 

6 

7 

8 

1 In 

5 In, 26 In. 

+1 

+1 

+1 

+1 

} +1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

}+• 

+1 

+1 

+1 

} +1 
4*1 
+i 
+i 
+i 
+i 
4*1 
+i 
+i 

-0.740 

- .733 

- .718 

- .709 

- .705 

- .694 

- .682 

- .672 

- .663 

- .659 

- .656 

- .653 

- .631 

- .624 

- .620 
- .602 

- .594 

- .582 

- .581 

- .552 

- .504 

- .492 

- .485 

- .462 

- .398 

- .354 

- .342 

- .336 

- .320 

- .306 

- .302 









-3.0 

-3.3 

-3.2 

-1.2 

+1.0 

-2.2 
-1.8 
-1.2 
-1.2 
-3.0 
-1.2 
-2.2 
+1.0 
-1.2 
+3.5 
+6.4 
+ .2 

- .4 

-1.0 

+ .7 
+2.4 
+ .1 

+ .7 

+ .7 

- .6 
-3.2 
+2.6 
-1.0 
- -2 
- -4 
-1-8 

2 Tn 

8 In,39 In, 50 In.... 

9 In, 99 In . 









3 In 









4 Tn 

13 In, 84 In . 









5 In 

/65 In, 72 In, 73 In, 

\ 106 In 

12 In, 37 In . 









6 In 









7 In 

20Inj43 In . 










48 In,59 In, 107 In... 
14 In,55 In,97 In.... 
31 In, 45 In . 


















10 In 









11 Tn 

19 In,41 In,96 In.... 

16 Tn 52 Tn 









12 Tn 









13 Tn 

15 Tn,67 Tn. .. 









14 In 

33 In,42 In, 103 In... 
6 Tn , 78 Tn . 









15 In 









16 Tn 

32 Tn r R0 Tn 









17 In 

40 In,95 In, 101 In... 
3 158 . 









18 

+0.53 

-i.4 

-0.4 

-2.6 

-1.4 


-0.4 


18 Tn 

11 In, 24 In, 35 In, 

\ 77 In 

9 Tn SO Tn, 51 Tn 



19 In 









20 Tn 

87 Tn, 100 Tn . 









24 

10 11 . 

+ .11 

- .1 

+ .1 

+ .3 

- .1 


+ *1 


21 Tn 

122 In, 75 In, 89 In, 
t 93 In 

98 145 



20 

+ .29 
+ .24 
.00 

+ .06 
+ .16 
+ .36 
+ .64 
+ .33 

+ .2 
-1.1 
-3.2 
+2.4 
-1.4 
- .8 
-1.6 
-2.4 

+ .7 
- .6 
-3.2 
+2.6 
-1.0 
- .2 
- .4 
-1.8 

- .8 
-1.6 
-3.4 
+2.2 
-1.4 
-1.5 
+2.8 
-2.4 

+ .2 
-1.1 
-3.2 
+2.4 
-1.4 
- .8 


+ .7 
- .6 
-3.2 
+2.6 
-1.0 
- .2 


17 

15* 162 



25. . 

13^ 143 . 



23 

96 141 



19 

14 * 166 



i$!. 

151 154 



31 

68 69 

-1.6 

-0.4 

14 . 

101.155 . 

-2.4 

-i.8 












































































































































































































































































120 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Observation equations for obtaining corrections to the coefficients of the gravity formula and to the depth of compensation —Con. 

ARRANGEMENT OF GROUPS—Continued. 


Group 

number 


15. 

10 . 

33. 

11 . 

13. 

9.. 

28. 

30. 

7.. 

8.. 
12 . 
6.. 

5.. 

1.. 
6C. 

4.. 
5C. 
27. 
4C. 

3.. 

2.. 
26. 
29. 
9C. 
2C. 
22 . 
21 . 
1C. 

5M 

6M 

1M 

4M 

3C. 

2M 

8C. 

7C. 

3M 


Including stations 


102,103,156. 

146, 147. 

54,55. 

172, 175. 

104, 135. 

/21,22,23, 84,209,212, 

\ 213,214 . 

42, 43, 44. 

47, 48. 

24, 125. 

210, 219. 

207, 211. 

25,26, 27. 

32, 133. 

28, 29, 30. 

17C,134. 

123, 130. 

16C, 88. 

75, 198. 

3C, 132. 

87, 132. 

85, 86. 

187, 201. 

50, 51, 52. 

1C. 87. 

23C,24C. 

182, 183. 

74, 184. 

7C 8C 

/18M. 28M' 31M, 33M, 
\ 34M, 35M 
TIM. 12M, 13M, 14M, 
15M, 16M, 17M, 
29M, 30M, 32M, 
36M 

1M, 2M. 

7M, 8M, 9M, 10M. 

27C,106. 

3M, 4M. 

38C, 41C. 

36C, 37C. 

5M, 6M. 


Coefficient of— 


+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+ 1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 
+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 

+1 


-0.297 

- .272 

- .256 

- .248 

- .214 

- .208 

- .204 

- .194 

- .185 

- .175 

- .164 

- .154 

- .096 

- .093 

- .082 
- .066 

- .049 

- .041 

- .031 

- .024 

- .016 
- .016 
- .011 
+ .001 
+ .001 
+ .009 
+ .010 
+ .020 

+ .039 


+ .044 

+ .053 
+ .060 
+ .080 
+ .199 
+ .212 
+ .218 
+ .236 


+0.85 
+ .26 
+ 1.02 
+ .50 
+ .08 

+ .20 

+ . 73 
+ .33 
+ .30 
+ .24 
+ .21 
+ .21 
+ .32 
+ .34 


+ .14 
’ + ’.’40' 


+ .09 
+ .32 
- .04 
+1.07 


+ .10 
- .01 


Constant term for solution number— 


- 1.0 
- 2.2 
-1.3 
+ 1.2 
+ 1.4 

-3.8 

- 2.2 
- .8 
-1.4 
+ 2.6 
+ 1.4 
- 1.6 
+ 1.2 
- .8 


+2.9 

— 6.8 


- .8 
- 1.8 
-3.0 
-3.5 


+4.0 

-2.4 


+0.6 
- 1.6 
+ .5 
+ 2.1 
+ 1.6 

-3.4 

- .7 
.0 

- .8 
+3.1 
+ 1.8 
- 1.0 
+1.8 

.0 

+ 1.1 

+3.3 

+1.4 

- 6.1 

+1.0 


- 1.2 
-3.0 
-1.4 
- 1.0 
+ 1.0 
+ 4.2 
-2.4 
- 1.6 


+ .4 


+1.2 

- .6 


-4.6 

- 2.8 

-7.8 

+ 2.0 

+2.4 

-4.2 

- 6.2 
+ 1.0 
- 2.1 
+2.7 
+2.0 
- 2.1 
+ 1.4 
-1.5 
+1.2 
+4.2 
+ 1.7 
-7.7 
+ .6 


-2.3 
-2.7 
-4.6 
- .8 
- .2 
+3.4 
- 2.2 
- 2.1 


+ .8 


+8.6 

+3.0 


- 1.0 

- 2.2 


+ 1.2 
+1.4 

-3.8 


-1.4 
+2.6 
+ 1.4 
-1.6 
+ 1.2 
- .8 


+2.9 


- .8 
-1.8 


+ 4.0 
-2.4 


-1.3 


-2.2 
- .8 


-6.8 


-3.0 

-3.5 


+0.6 

-1.6 


+2.1 

+1.6 

-3.4 


- .8 
+3.1 
+ 1.8 
- 1.0 
+1.8 
.0 

+ 1.1 

+3.3 

+1.4 


+1.0 


- 1.0 
+ 1.0 
+4.2 
-2.4 
-1.6 


+ .4 


+0.5 


- .7 
.0 


- 6.1 


-3.0 

-1.4 


+1.2 

- .6 


+ 0.6 
- 1.6 
+ .5 
+2.1 
+ 1.6 

-3.4 

- .7 
.0 

- .8 
+3.1 
+ 1.8 
- 1.0 
+1.8 

.0 

+ 1.1 
+3.3 
+ 1.4 
- 6.1 
+ 1.0 


- 1.2 

-3.0 

-1.4 

- 1.0 

+1.0 

+4.2 

-2.4 

- 1.6 

- 1.5 


-1.3 

+ 1.2 
-3.0 
+ .4 
-2.4 
+1.2 
- .6 
-5.2 


The first column of the table on pages 115-119 contains the number of the station. Numbers 
without any letters appended refer to the United States stations given in the list on pages 50-52; 
the numbers followed by the letter “C” refer to the Canadian stations on page 54; the numbers 
followed by the letters “In” refer to the Indian stations given in the fist on page 56; and the 
numbers followed by the letter “M” refer to the stations in the fist on page 57. 

The data in the above tables come from pages 50-60 and 103-105. All stations having 
anomalies numerically greater than 0.070 dynehave been excluded. For convenience the unit of n' 
and therefore of the other quantities involved, has been taken as 0.01 dyne. The unit distance in 
terms of which 2 is expressed in these equations is 28.4 km.; that is, the int erval between the depths 
at which the various anomalies for stations in the United States are tabulated on pages 103-105. 
If the correction for topography and compensation be assumed to change uniformly with chang- 

ing depth of compensation, that is, if c = ^- is constant, then the value of c, with the units 

adopted, is the difference between the total corrections for topography and compensation for 
two depths differing 28.4 km., expressed in units of hundredths of a dyne. An examination of the 
differences in the table on pages 100—102 will show that these are fairly constant, allowance being 
made for the effect of omitted decimals. When the observation equations were formed, these 
quantities carried to one more decimal place than is given on pages 100-102 were available. A 
specimen of such data is given in connection with station 195, Lander, Wyo., on page 99. From 
the data for this station the following mean rates of change, in the units adopted, are deduced: 


From 42.6 km. 
From 56.9 km. 
From 85.3 km. 
From 113.7 km. 
From 127.9 km. 
From 156.25 km. 


to 56.9 km. =2 (-3.62+3.70)=+0.16 
to 85.3 km. = —3.28+3.62 =+0.34 

to 113.7 km. = -2.75+3.28 =+0.53 

to 127.9 km. =2 (-2.48+2.75)=+0.54 
to 156.25 km.= -1.98+2.48 =+0.50 
to 184.6 km. = -1.33+1.98 =+0.65 












































































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


121 


A preliminary investigation indicated that the depths of compensation in nearly all solu¬ 
tions would fall between 56.9 km. and 85.3 Ion., or else very little below 56.9 km. The values 
of c used in the table of observation equations are therefore the mean rates of change between 
56.9 km. and 85.3 km. These c’s are to he used only in connection with solutions for which the 
depth of compensation is determined. In these solutions the constant term, —n', is based on a 
depth of 56.9 km. In the second solution for mountain stations, in which the resulting depth 
is 94.9 km., the anomalies for depth 113.7 km. and the corresponding c’s were used. These are 
not shown in the table of observation equations. 

In order not to give too great influence to a small region that might contain many gravity 
stations, the following arbitrary procedure was adopted. A solitary station having no other 
station within 1 degree of it, either in latitude or longitude, gave a single observation equation 
of weight unity. If a number of stations occurred so that their latitudes were all within 1 
degree of one another, and likewise their longitudes, these stations were made to constitute a 
group and the mean of the observation equations of the separate stations of the group was 
taken as the observation equation of the group, with weight unity. In taking this mean for 
the group, stations within a radius of 8 miles were treated as a single station by taking their mean, 
and giving the mean only the weight of a single station in averaging it with the other members 
of the group. An example of this is group 1, which contains stations 28, 29, and 30, which are, 
respectively, Worcester, Boston, and Cambridge. The mean of the anomalies at Boston and 
Cambridge is +0.013 dyne and this is given equal weight in combining with the anomaly at 
Worcester of —0.012 dyne, giving a final mean for the group of 0.000 dyne. In the list of 
observation equations, stations that are used only as part of a group are designated by a 
reference mark which refers to a footnote when the details of the grouping require special men¬ 
tion. The latter part of the list of observation equations is made up of the mean equations for 
the various groups. When the observations were combined into zones of latitude, the mean 
of a group was given the same weight as a solitary station, the group being assigned to a zone 
according to the average latitude of its component members. 

The normal equations were made up in the usual way. The probable error of z is found in 
the usual way from the solution of the normal equations. The quantities y ( , B, and/ are func¬ 
tions of x and y. Their probable errors are found by methods given in standard text books 
on the method of least squares.* (See note, p. 98.) These methods all require a knowledge 
of the numerical values of the derivatives of the functions in question with respect to the 
unknown quantities of the observation equations. 

The formulas (partial derivatives), easily obtained from (4b) and (3) on page 113, and from 
the definitions of x and y near top of page 114, are 



dy e 

dy 







(8) 


dB = _B ' 
d x y e 
dB 2 +B 
dy y t 



(9) 


* For example, Wright and Hayford, Adjustment of Observations, p. 137, or Helmert, “Die Ausgleichungsrechnung,” 2te auflage, p. 180. 
t x and y are independent of z, according to assumption, and therefore y ( , which depends only on x and y, is also independent of z; similarly for 
B and f. Asa matter of fact, the redistribution of attracting matter implied in the correction for isostatic compensation will change somewhat the 
form of the level surfaces and the intensity of gravity. For the earth considered as a whole the change is slight. Prof, de Sitter (in the Tvoninklikje 
Akademie van Wetenschappen te Amsterdam, Proceedings of the Section of Sciences, Vol. XVII, pt. 2, p. 1295) makes some approximate mechanical 
quadratures and concludes that for the geoid as idealized by isostatic compensation to a depth of 114 km. 1// will be 0.14 less than for the actual 
geoid. The effect on gravity at the equator is to make the idealized gravity greater than the true by less than 0.001 dyne. For smaller changes in 
depth the effects would be correspondingly less, and the assumptions made are ev dently not seriously vitiated. 







122 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


dm _ TO 
d~X~ ~~ Ye 

dm_m 
dy~ 7 * 

dm 2 3 

L/__l + lZ m+ A 5 

d£~ + 14 + 21 

d/ = d/dro + d/d5 
d x dm 5 i t dZ? d x 
df = dfbm dfdB 
d y dm d y + dB d y 


d z 


= 0 


(10) 


These derivatives are so nearly constant that for the purpose in hand they could be com¬ 
puted once for all with average values of the quantities involved. 

It will be found that the flattening depends almost wholly on y, for i s about — 0.0000203 


(in the units used in forming the observation equations) as against ^ = —0.000000034. A 

change of unity (i. e., 0.01 dyne) in the value of x will appear only in the third decimal of 1 If, so 
if it is desired to hold the flattening unchanged in the determinations it will be sufficient to 
make y = 0, or, if some other flattening be fixed on in advance, in the adjustment the corre¬ 
sponding value of y may be determined without regard to the possible change in x. This was 
done in solutions lc, Id, and some others. 

In comparing various gravity formulas, which differ among themselves in every term, the 
most convenient single number to afford a basis of comparison is the mean value of y 0 over the 
unit sphere. The general expression for this is 

Mean value = y £ (l— (11) 


In the case of the solutions given here this is equivalent to 

Mean value ==979.75485 +x — \y (12) 

x and y being expressed in dynes instead of in units of 0.01 dyne, as in the observation and 
normal equations. The mean values resulting from the various adjustments are given on 
page 129. 

The set of solutions numbered “1” in the preceding table was derived from all stations 
situated in the United States proper, except No. 218, North Tamarack, Mich., for which the data 
were not available in time, and stations 53 and 56 in Seattle, Wash., which were excluded 
because of their large anomalies. In all these stations the constant terms are for depth 56.9 
lan. and the s’s are corrections to that depth. In solution la each solitary station and each 
group of stations is given equal weight. The normal equations are 

173x - 34.572y + 42.17s - 182.3 = 0 

- 34.572x + 13.2991 y - 11.8632s + 26.6250 = 0 

42.17x - 11.86321/ + 26.3941s - 46.181 = 0 

From these x = +1.2934, y= + 1.7989, s= +0.4918, and the formula for y 0 is 

7o = 978.025(l +0.005339 sin 2 0-0.000007 sin 2 20) 

±5 ±11 

The depth of compensation is 70.9 + 10.0 km. and the reciprocal of the flattening is 301.4 + 1.0. 







INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


123 


In solution lb the stations or groups were assigned to seven zones and each station or group 
was given a weight inversely proportional to the number of stations and groups in the zone. 
This process must be substituted for the simpler one of using a mean equation for each zone, 
which would be practically equivalent if no depth of compensation were to be determined, 
because the c’s, unlike the other coefficients, vary widely within the zone. 

The boundaries of the zones are in latitude 31°, 34°, 37°, 40°, 43°, 46°, and 49°, the latter 
being the northern boundary of the United States. The zones are all three degrees in width, 
except the southernmost, which extends from station 1 (Key West, Fla.) in latitude 24° 33'.6 
to latitude 31° 00'. It was widened in order to include a sufficient number of stations to be 
representative. 

The normal equations are: 

lx -1.5606?/+ 1.74242 — 7.5950 = 0 
— 1.5606x4-0.64982/ —0.54482 + 1.2431 =0 
1.7424x - 0.5448 y + 1.05032- 1.8980 = 0 
From these x= +1.3574, y= +1.7233, 2 = +0.4490. The formula for y 0 is 

To = 978.026(1 +0.005337 sin 2 0-0.000007 sin 2 20) 

±5 ±11 

The depth of compensation is 69.6 ± 10.4 km. and the reciprocal of the flattening 301.3 ± 1.0. 

The flattenings deduced from la and lb are not supported by determinations from other 
methods, which would indicate that the assumed flattening of 1/29S.2 is more nearly correct. 
It was therefore decided to hold the flattening at this figure. This may be done with sufficient 
accuracy by letting y = 0. 

Using separate stations and groups, we have for solution lc, by omitting the second equation 
in la and putting y = 0 in the others, 

173x + 42.172— 182.3 = 0 

42.17x + 26.39412 —46.181 =0 

From these x= +1.0274, z= +0.1082, and the formula for y 0 is 

To = 978.040(1 +0.005302 sin 2 0-0.000007 sin 2 20) 

±1 

The depth of compensation is 60.0 + 9.5 km. 

This formula is referred to as the Coast and Geodetic Survey formula of 1916 for the United 
States. 

If the anomalies at stations in the United States were due only to erroneous values of the 
equatorial gravity and of the depth of compensation used in the computation of the theoretical 
gravity, then this formula would be perhaps the best obtainable from the data at hand. But, as is 
shown on page 63, under the heading “Relation between the gravity anomalies and the topogra¬ 
phy/' and on page 70, under the heading ‘ ‘ Relation between the gravity anomalies and the geologic 
formation/' the prevailing sign of the anomalies at stations on the seacoast and on Cenozoic 
formations is evident^ due in part to some deviation from the normal of the densities in the strata 
of the upper crust which is systematic in its nature. The depth computed from the anomalies 
may be, and probably is, greatly influenced by this systematic effect. It is shown in other parts 
of this volume that a larger depth than 60 km. is probably nearer the truth. The equatorial 
value of gravity is not affected materially by the negative anomalies which predominate at the 
stations near the coast and in Cenozoic formation, as they are offset in great part by the anoma¬ 
lies in other formations which tend to be positive. (See pp. 70 to 78.) The anomalies (called 
the Hayford 1916 anomalies) based on the Coast and Geodetic Survey formula for 1916 for the 


124 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


United States are shown in the table on pages 103-106 for purposes of comparison with the 
anomalies by the 1912 formula of the Coast and Geodetic Survey (called the Hayford 1912 
anomalies), which is based on the greater depth of compensation, 113.7 km. 

From other data a flattening of 1/297 has been determined. To use this flattening in deter¬ 
mining x and z (solution Id), put y = — 0.642 in the first and third equations of la. The resulting 
equations are: 

173x + 42.172—160.10 = 0 

42.17x4-26.39412 —38.565 = 0 

From these x = 4-0.9322, 2 = —0.0286 and the formula for y 0 is 

7 o = 978.046 (14-0.005289 sin 2 0-0.000007 sin 2 20) 

±1 

and the depth of compensation is 56.1 ±9.7 Ion. 

In solution le the flattening is held at 1/298.2 and the stations are grouped by zones, as in 
solution lb. 

The normal equations for le are: 

7x +1.74242 -7.5950 = 0 
1.7424x +1.05032 -1.8980 = 0 

From these x = +1.0820, 2 = +0.0122, and the formula for y 0 is 

7 o = 978.041 (1+0.005302 sin 2 0-0.000007 sin 2 20) 

±1 

The depth of compensation is 57.2 ±9.8 km. 

The solutions numbered 2a and 2b include stations in the United States proper and the 
Dominion of Canada. No determination of the depth was possible, since no information as 
to the correction for topography and compensation of the Canadian stations was available for 
depths other than 113.7 km. In solution 2a each station and each group was given unit weight. 
The normal equations for this solution are:° 

208x —31.281?/ —96.1=0 

- 31.281x +13.808183 y + 3.2079 = 0 

From these x= +0.6478, y= +1.2351, and the formula for y 0 is 

7 o = 978.024 (1 +0.005327 sin 2 0-0.000007 sin 2 20) 

±4 ±9 

The reciprocal of the flattening is 300.4±0.8. 

Solution 2b is the same as 2a, except that zones were used as in lb, though with somewhat 
different boundaries for the zones. 

The normal equations are: 

7x—1.32y —2.676 = 0 

-1.32x + 0.56230?/ + 0.060917 = 0 

From these x= +0.6493, y= +1.4158, and the formula for 7 0 is 

7 o = 978.022 (1 +0.005331 sin 2 0-0.000007 sin 2 20) 

±4 ±9 

The reciprocal of the flattening is 300.7 ±0.8. 

a In forming thesenormal equations the data used for the stations in Canada were those first communicated to the Survey. Afterwards revised 
values were sent, which appear in the table of observation equations. The corrections are too slight to affect the result seriously. 



INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


125 


In the solutions numbered 3a and 3b the anomalies are found by the free-air method of 
reduction (correction for elevation, but not for topography and compensation). The stations 
are the same as those in solutions 2a and 2b. In solution 3a each station and each group is 
given emit weight, and the resulting normal equations are: ° 

208x-31.281?/-161.1=0 

- 31.281a; +13.8082?/ + 52.8456 = 0 

From these x= +0.3018, y= —3.1435, and the resulting formula for y 0 is 

7 o = 978.064 (1+0.005238 sin 2 0- 0.000007 sin 2 20) 

±5 ±12 

The reciprocal of the flattening is 292.6 + 1.0. 

In solution 3b each zone is given equal weight, the zones being the same as in solution 2b. 
The normal equations are: 

7a:-1.320?/-5.563 = 0 

-1.320a: + 0.56230?/ +1.954694 = 0 

From these x= +0.2498, ?/= —2.8899, and the formula for y 0 is 

7 o = 978.061 (1 + 0.005243 sin 2 0-0.000007 sin 2 20) 

±7 ±17 

The reciprocal of the flattening is 293.0 + 1.4. 

In order to test the constancy of the depth of compensation in various regions, the stations 
in the United States lying east of the ninety-eighth meridian were treated separately from those 
lying west of it. Solutions 4a and 4b are based on those stations east of the ninety-eighth 
meridian. In solution 4a each station and each group is given unit weight, and a depth of 
CDmpensation, a value for the flattening, and the equatorial value are determined. The 
values of — n' are for depth of 56.9 km. The normal equations for 4a are: 

118x-26.723?/+ 26.212-80.1 = 0 
— 26.723a; +10.265?/ —8.1672+ 17.691 =0 
26.21a:-8.167?/ +11.5052-17.241=0 

From these x= +0.7100, ?/= +0.0698, 2 = -0.0695, and the formula for y 0 is 

7 0 = 978.036 (1+0.005303 sin 2 0-0.000007 sin 2 20) 

±6 ±14 

The depth of compensation is 54.9 ± 16.8 km., and the reciprocal of the flattening is 298.3 ±1.2. 

In solution 4b the conditions are the same as for 4a except that the flattening is held as 
1/298.2, the value resulting from Helmert’s formula of 1901. The normal equations are 

118a; + 26.2l2 —80.1=0 
26.21a: +11.5052- 17.241 = 0 

From these x = +0.7004, 2 = -0.0970, the formula for y 0 is 

7 0 = 978.037 (1+0.005302 sin 2 0-0.000007 sin 2 20) 

±2 

and the depth of compensation is 54.1 ±14.9 km. 

The solutions numbered 5a and 5b are based on stations in the United States west of 
the ninety-eighth meridian, treated in a way similar to those used in solutions 4a and 4b. In 


a See footnote on p. 124. 




126 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


solution 5a each station and each group is given unit weight. The values of — n' are for depth 
56.9 km. The normal equations are: 

55x - 7.849 y + 15.96s -102.2 = 0 
- 7.849x + 3.0345y - 3.6967s + 8.9343 = 0 
15.96x - 3.6967y + 14.8890s- 28.940 = 0 

From these x = +2.2099, y= +3.2312, 2 = +0.3772, and the formula for 7 0 is 

7 0 = 978.020 (1 + 0.005368 sin 2 <£-0.000007 sin 2 2<£) 

±10 ±22 

The depth of compensation is 67.6 ±12.9 km., and the reciprocal of the flattening is 304.1 ±2.0. 

In solution 5b the conditions are the same as for 5a except that the flattening is held fixed 
at 1/298.2. The equations, giving unit weight to each station and group, are 

55x+15.96s-102.2 = 0 
15.96x + 14.8890s - 28.940 = 0 

From these x= +1.8784, s= -0.0698, and the value of 7 0 is given by 

7 0 = 978.049 (1+0.005302 sin 2 0-0.000007 sin 2 2<£) 

±2 

The depth of compensation is 54.9 + 12.6 km. 

The solutions with separate stations in mountainous regions gave greater depths than other 
solutions for other groups of stations in the United States, and as it is reasonably certain that 
the single-station method gives a better value of the depth than the group method, it was 
decided to make solutions for the stations in the United States west of the ninety-eighth meridian 
without groups; that is, by the separate-station method. In the first of the two solutions, called 
5c, the equatorial gravity, the flattening, and the depth of compensation were determined. 

The normal equations are 

64x — 9.092y + 21.922— 127.1 = 0 
— 9.092x +3.319338y —4.549952+11.2513 = 0 
21.92x - 4.54995 y + 22.64222 - 53.946 = 0 

From these x= +2.2016, y= +4.1200, 2 = +1.0790, and y 0 is given by 

7 o = 978.011 (1+0.005387 sin 2 <£-0.000007 sin 2 2<£) 

±19 ±21 

The depth of compensation is 87.5 ±10.6 km. and the reciprocal of the flattening is 305.8 + 1.9. 
In the solution 5d the flattening was held at 1/298.2. The normal equations are: 

64X + 21.922-127.1=0 
21.92x + 22.64222- 53.946 = 0 

From these x = +1.7503, 2 = +0.6881 and y 0 is given by 

7 o = 978.048 (1 + 0.005302 sin 2 <£-0.000007 sin 2 2<£) 

±2 

The depth of compensation is 76.4 ±10.8 km. 

If the Canadian stations east of the ninety-eighth meridian be joined with those in the 
United States, no determination of the depth of compensation is possible, since the only depth 
for which the corrections for topography and isostatic compensation are available for Canadian 
stations is 113.7 km. In solution 6 this depth is used and each station or group east of the 
ninety-eighth meridian in Canada or the United States is given unit weight. The normal 
equations are then ° 

146x — 25.174y —35.6 = 0 
- 25.174x + 10.455634y + 2.5569 = 0 


a See footnote on p. 124. 



INVESTIGATION’S OF GRAVITY AND ISOSTASY. 127 

From these x= +0.3448, y = +0.5857, and the formula for y 0 is 

7 o = 978.028 (1 + 0.005314 sin 2 0-0.000007 sin 2 20) 

±4 ±11 

The reciprocal on the flattening is 299.2 ± 1.0. 

Solution 7 is based on stations in the United States and Canada west of the ninety-eighth 
meridian. The depth is fixed at 113.7 km. and each station or group is given equal weight. 
The normal equations are 

. 62x — 6.107^-59.3 = 0 
— 6.107z + 3.352549y +0.8568 = 0 

From these x= +1.1349, y= +1.8118, and the formula for y 0 is 

7o = 978.023 (1 + 0.005339 sin 2 0-0.000007 sin 2 20) 

±8 ±17 

The reciprocal of the flattening is 301.5 ± 1.5. 

The solutions numbered 8a and 8b are based on all available stations in the world 
between the latitudes of station 179ln, Bombay (India) and station 6 M, Scharfenstein (Ger¬ 
many). The only depth of compensation for which data are available is 113.7 km., and this 
has therefore been held fixed. Stations with an anomaly numerically exceeding 0.070 dyne 
based on Helmert’s formula of 1901 were excluded. It was found that 358 stations could be 
used. For solution 8a the stations and groups of stations were divided into 11 zones each 3 
degrees of latitude in width; the southernmost zone includes Bombay and extends to the 
twenty-second parallel. The other bounding parallels are the twenty-fifth, twenty-eighth, etc. 
All stations used in these solutions are in north latitude. 

Results for the individual zones. 


Zone. 

Bounding 

parallels. 

Number of 
stations or 
groups. 

Mean value 
of — cos2 <j> 

Mean 

anomaly. 


O 

22 

6 

-0.748 

Dynes. 

+0.0212 


22-25 

14 

- .680 

+ .0176 


25-28 

13 

- .609 

- .0062 


28-31 

17 

- .510 

+ .0048 


31-34 

21 

- .420 

— .0009 


34-37 

25 

- .323 

+ .0026 


Zone. 

Bounding 

parallels. 

Number of 
stations or 
groups. 

Mean value 
of — cos2 <f> 

Mean 

anomaly. 

7. 

O 

37-40 

33 

-0.218 

Dynes. 
-0.0014 

8 . 

40-43 

27 

- .115 

+ .0069 

9. 

43-46 

41 

- .017 

+ .0099 

10 . 

46-49 

41 

+ .074 

+ .0108 

11 . 

49-52 

14 

+ .185 

+ .0056 


There is a total of 252 separate stations and groups of stations. Each zone was given unit 
weight. The normal equations that follow from these are 

llx —3.381y —7.09 = 0 
- 3.381x + 2.034353 y + 2.57810 = 0 

From these x= +0.5213, y= —0.4008, and the formula for y 0 is 

7 0 = 978.039 (1 + 0.005294 sin 2 0-0.000007 sin 2 20) 

±4 ±12 

The reciprocal of the flattening is 297.4 ±1.0. 

The fact that the mean anomalies for some of the zones are based on comparatively few 
stations or groups of stations as compared with the other zones suggests that it would be of 
interest to weight each zone proportionately to the number of stations it contains. This process 
is (except for probable errors) almost exactly equivalent to that of giving each station and each 
group unit weight. With weights thus taken, the normal equations for solution 8b, are 

252z —52.855y— 149.1=0 
- 52.855x + 28.027 y + 23.9 = 0 






























128 U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 

From these s = +0.6829, t/ = +0.4352, and the formula for 7 0 is 

7 o = 978.032 (1 + 0.005311 sin 2 <£-0.000007 sin 2 2 <£) 

±4 ±11 

The reciprocal of the flattening is 298.9 ± 1.0. 

On pages 63-G7 is given a list of anomalies at stations in the United States computed from the 
United States Coast and Geodetic Survey formula of 1916; that is, for solution lc. This formula 
with depth 60.0 km. represents the observations somewhat better than the 1912 formula with 
depth 113.7 km. except for the 20 stations in mountainous regions above the general level, for 
which the average anomaly with regard to sign is +0.016 dyne by the 1916 formula. It is 
therefore natural to inquire what formula and what depth would fit those stations better. The 
effect of the change of depth on the computed compensation is large for these stations, so that 
a depth of compensation would be better determined from them than from an equal number of 
stations elsewhere. However, it seemed to be illogical to take only the stations above the 
general level and to exclude other stations in the same regions, perhaps within a few miles. 
Therefore the 36 stations in mountainous regions below the general level (see p. 108) were like¬ 
wise included in the adjustment. There is no separate column for the constant terms of this 
solution in the table of observation equations on pages 115 to 120. 

This adjustment was made in two ways. First the groups were broken up, each station 
being taken by itself, and only the 56 stations in mountainous regions were included. Second, 
where the stations occurred near together groups were used, just as in other cases. These 
groups included four stations not in mountainous regions. 

When the groups were broken up and each station was given unit weight the normal equa¬ 
tions for this solution (called 9a) became: 

56s- 9.017 t/ +27.482 -38.2 = 0 
- 9.017x + 2.6091714^/ - 5.185052 + 1.6404 = 0 
27.48s— 5.18505y+ 18.7226s- 15.279 = 0 

From these s=+1.3506, y = +3.8278, 2 = — 0.1061. The anomalies and the c’s in this solu¬ 
tion are computed for the depth of 113.7 km. and the 2 is a correction to that depth. The re¬ 
sulting formula for y 0 is 

7 o = 978.005 (1 + 0.005380 sin 2 <£-0.000007 sin 2 2 <£) 

±14 ±31 

The reciprocal of the flattening is 305.2 ±2.9 and the depth of compensation is 110.7 ±20.3 km. 

Solution 9b is based on the same data, but the flattening was held fixed at 1/298.2. The 
normal equations for solution 9b are 

56s+ 27.482-38.2 = 0 
27.48s + 18.7226 2 - 15.279 = 0 

From these s= +1.0066 and y= —0.6613. The formula for y 0 is 

7 o = 978.040 (1 + 0.005302 sin 2 <£-0.000007 sin 2 2 <£) 

±4 

The depth of compensation is 94.9 ±19.7 km. 

When the usual groups are taken, the normal equations for the solution (called 9c) are 

44s - 6.8797/ +19.252-64.9 = 0 
- 6.879s + 2.056157 y - 4.23457 2 + 9.057 = 0 
19.25s -4.23457t/ + 16.26412-29.779 = 0 

From these s=+1.5433, y =+1.6542, 2 =+0.4350. The anomalies and c’s in this solution 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


129 


are computed for the depth 56.9 km. and the z is a correction to this depth. The resulting 
formula for y 0 is 

To = 978.029 (1+0.005336 sin 2 0- 0.000007 sin 2 20) 

The reciprocal of the flattening is 301.2, and the depth of compensation is 69.3 km. 

In solution 9d the flattening is held fixed at 1/298.2 hut the remaining conditions are the 
same as in the solution 9c. The normal equations for solution 9d are 

44x+ 19.252 — 64.9 = 0 
19.25a; + 16.26412- 29.779 = 0 

From these x= + 1.3977, and 2 = +0.1766. The resulting formula for y 0 is 

7 o = 978.044 (1+0.005302 sin 2 0-0.000007 sin 2 20) 

and the depth of compensation is 61.9 km. 

It is evident that the method of grouping high and low stations in forming the equations 
destroys the peculiar sensitiveness of the high stations to a change in depth. Therefore the 
values of the depth by the group solution (9c) should not be considered as having a strong 
weight as compared with the values of the depth by the single-station solution (9b). 

The author believes that the depths derived from the single-station solution for moun¬ 
tainous regions are nearer the truth even for the whole United States than any other depth 
determined from other groups of gravity stations. (Seep. 112.) The solutions of separate 
stations in the western part of the United States give values for the depth of compensation 
which are greater than for other solutions except those mentioned above. The stations in 
the West are, in general, either in mountainous regions or on high plains. 

The results of the foregoing solutions are summarized in the following table, which also 
contains some additional items of information, namely, the mean value of gravity and the 
probable error of an observation of unit weight. Except in the column for the mean value of 
gravity and in the lines for solutions 9c and 9d the presence of a value for the probable error 
of a quantity indicates that the quantity in question was determined by the solution itself, and 
the absence of a value for the probable error indicates that the quantity was fixed in advance. 

Constants of the gravity formulas and related quantities as derived from the various solutions. 


Solution No. 

Equatorial 
value of grav¬ 
ity. 

Coefficient of 
sin 2 <£. 

Mean value of 
gravity for the 
earth. 

Reciprocal of 
flattening. 

Depth of com¬ 
pensation. 

Probable error 
of an observa¬ 
tion of unit 
weight. 


Dynes. 


Dynes. 


Km. 

Dynes. 


978.025± 4.9 

0.005339±11.5 

979.762 

301. 4 ±1.0 

70.9 ±10.0 

±0.0133 


978.026 ± 4.6 

.005337 ±10.7 

979.763 

301.3 ±1.0 

69.6 ±10.4 

o± .0027 


978.040 ± 1.3 

.005302 

979.765 

298.2 

60.0± 9.5 

± .0135 


978.046± 1.3 

. 005289 

979.766 

297.0 

56.1± 9.7 

± .0137 


978.041 ± 1.3 

.005302 

979.766 

298.2 

57.2± 9.8 

«± .0027 


978.024 ± 3.9 

. 005327 ± 9.0 

979.757 

300.4 ±0.8 

113.7 

± .0133 


978.022 ± 3.7 

. 005331 ± 9.2 

979.757 

300. / i0* 8 

113.7 

o± .0025 

3^ . 

978.064± 5.1 

.005238±12.0 

979.768 

292.6± 1.0 


± .0176 

3b . 

978.061 ± 6.8 

.005243 ±16.6 

979. 767 

293.0±1.4 


o± .0045 


978.036 ± 6.1 

.005303 ±14.1 

979.762 

298.3±1.2 

54.9 ±16.8 

± .0126 


978.037 ± 1.6 

. 005302 

979.762 

298.2 

54.1 ±14.9 

± .0125 


978.020± 9.7 

.005368 ±21.6 

979. 766 

304.1 ±2.0 

67.6±12.9 

± .0138 


978.049 ± 2.3 

. 005302 

979.774 

298.2 

54.9 ±12.6 

± .0142 


978.011 ± 9.5 

.005387 ±21.1 

979.763 

305.8± 1.9 

87.5 ±10.6 

± .0141 


978.048 ± 2.3 

.005302 

979.772 

298.2 

76.4 ±10.8 

± .0148 


978.028± 4.5 

.005314 ±10.8 

979.756 

299.2± 1.0 

113.7 

± .0130 


978.023 ± 7.6 

.005339 ±16. 8 

979.760 

301.5± 1.5 

113.7 

± .0136 


978.039 ± 4.3 

. 005294±11.8 

979.761 

297.4± 1.0 

113.7 

o± .0057 


978.032 ± 4.4 

.005311 ±10.9 

979.760 

298.9± 1.0 

113.7 

± .0220 


978.005 ±14.4 

.005380±31.2 

979.756 

305.2 ±2.9 

110 .7±20.3 

± .0156 


978.040± 4.0 

.005302 

979.765 

298.2 

94.9 ±19.7 

± .0158 

Qp . 

978.029 

.005336 

979.765 

301.2 

69.3 


<4rl . 

978.044 

.005302 

979.769 

298.2 

61.9 










i* The observation of unit weight is a zone. 

59:187 17-9 




















































130 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


STATEMENT CONCERNING THE VARIOUS SOLUTIONS THE RESULTS OF WHICH ARE GIVEN IN THE 

ABOVE TABLE. 

In the solutions in which separate stations and groups of stations were used, each separate 
station and each group of stations was given unit weight. 

In the solutions in which the stations were taken by zones, each zone was given unit weight, 
except in solution 8b. 

UNITED STATES STATIONS, SOLUTIONS la TO le. 

la. Separate stations and groups of stations were used in the determination of equatorial gravity, the flattening and 

the depth of compensation. 

lb. Zones were used in the determination of equatorial gravity, the flattening, and the depth of compensation. 

lc. Separate stations and groups of stations were used and the flattening was held fixed at 1/298.2 in the determina¬ 

tion of equatorial gravity and the depth of compensation. 

l d. Separate stations and groups of stations were used and the flattening was held fixed at 1/297 in the determina¬ 

tion of equatorial gravity and the depth of compensation. 

le. Zones were used and the flattening was held fixed at 1/298.2 in the determination of equatorial gravity and the 

depth of compensation. 

UNITED STATES AND CANADIAN 8TATIONS, SOLUTIONS 2a AND 2b. 

2a. Separate stations and groups of stations were used and the depth was held fixed at 113.7 km. in the determina¬ 
tion of equatorial gravity and the flattening. 

2b. Zones were used and the depth was held fixed at 113.7 km. in the determination of equatorial gravity and the 
flattening. 

UNITED STATES AND CANADIAN STATIONS BY THE FREE-AIR METHOD OF REDUCTION, SOLUTIONS 3a AND 3b. 

3a. Separate stations and groups of stations were used in the determination of equatorial gravity and the flattening. 
3b. Zones were used in the determination of equatorial gravity and the flattening. 

UNITED STATES STATIONS EAST OF THE NINETY-EIGHTH MERIDIAN, SOLUTIONS 4a AND 4b. 

4a. Separate stations and groups of stations were used in the determination of equatorial gravity, the flattening, and 
the depth of compensation. 

4b. Separate stations and groups of stations were used and the flattening was held fixed at 1/298.2 in the determina¬ 
tion of equatorial gravity and the depth of compensation. 

UNITED STATES STATIONS WEST OF THE NINETY-EIGHTH MERIDIAN, SOLUTIONS 5a TO 6d. 

5a. Separate stations and groups of stations were used in the determination of equatorial gravity, the flattening, and 
the depth of compensation. 

5b. Separate stations and groups of stations were used and the flattening was held fixed at 1/298.2 in the determina¬ 
tion of equatorial gravity and the depth of compensation. 

5c. Separate stations only were used in the determination of equatorial gravity, the flattening, and the depth of com¬ 
pensation. 

5d. Separate stations only were used and the flattening was held fixed at 1/298.2 in the determination of equatorial 
gravity and the depth of compensation. 

UNITED STATES AND CANADIAN STATIONS EAST OF THE NINETY-EIGHTH MERIDIAN, SOLUTION 6. 

6. Separate stations and groups of stations were used and the depth was held fixed at 113.7 km. in the determination 

of equatorial gravity and the flattening. 

UNITED STATES AND CANADIAN STATIONS WEST OF THE NINETY-EIGHTH MERIDIAN, SOLUTION 7. 

7. Separate stations and groups of stations were used and the depth was held fixed at 113.7 km. in the determination 

of equatorial gravity and the flattening. 

STATIONS IN THE UNITED 8TATES, CANADA, SWITZERLAND, INDIA, ITALY, GERMANY, AND AUSTRIA, SOLUTIONS 8a AND 8b. 

8a. Zones were used, the zones having equal weight, and the depth was held fixed at 113.7 km. in the determination 
of the equatorial gravity and the flattening. 

8b. Zones were used, the zones weighted according to the aggregate number of stations and groups in a zone, and the 
depth was held fixed at 113.7 km. in the determination of equatorial gravity and the flattening. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


131 


UNITED STATES STATIONS IN MOUNTAINOUS REGIONS, SOLUTIONS 9a TO 9d. 

9a. Separate stations only were used in the determination of equatorial gravity, the flattening, and the depth of 
compensation. 

9b. Separate stations only were used and the flattening was held fixed at 1/298.2 in the determination of equatorial 
gravity and the depth of compensation. 

9c. Separate stations and groups of stations were used in the determination of equatorial gravity, the flattening, and 
the depth of compensation. 

9d. Separate stations and groups of stations were used and the flattening was held fixed at 1/298.2 in the determina¬ 
tion of equatorial gravity and the depth of compensation. 

For completeness and for comparison with the above formulas for the intensity of gravity 
there is given here Helmert’s most recent formula.® With probable errors attached it reads: 

g 0 = 978.052[1 + 0.005285 sin 2 0-0.000007 sin 2 20 + 0.000018 cos 2 0 cos2(X + 17°)] 

±3 ±5 ±3 ±4 

in which 0, as usual, is the geographic latitude and X is the longitude from Greenwich, east longi¬ 
tude being positive. The formula corresponds to a spheroid with three unequal axes, the shorter 
equatorial axis being in longitude 73° east from Greenwich and the longer, which exceeds the 
shorter by 230 m., in longitude 17° west of Greenwich. The reciprocal of the mean polar 
flattening is 296.7 + 0.4. The mean value of gravity over the sphere is 979.771 dynes. The 
formula is based upon 410 stations in all parts of the world selected for being neither too near 
to the coast nor to mountainous regions and upon certain coast stations which were given 
reduced weight. The coefficient of sin * 2 20 is based on theory. (See p. 113.) The coast 
stations were used in determining all other constants except the first one, which from coast 
stations alone had the special value of 978.068 dynes. The precise number of coast stations 
is not given. The formula, when the first coefficient is used as 978.052, represents gravity 
reduced by the free-air method for stations in the interior and not in mountainous regions. 
No tests have yet been made to determine how well this formula represents gravity in the 
United States. 

HELMERT’S DEPTH OF COMPENSATION FROM GRAVITY OBSERVATIONS. 

Helmert derived a depth of compensation of about 120 km. from data for 51 selected 
coast stations distributed throughout the earth’s surface. 6 He used in his determination the 
differences between the observed values of gravity reduced to sea level by the free-air method 
and the values at sea level computed by his 1901 formula. The observed values were in general 
considerably greater than those computed. 

The stations were arranged in several groups, each group containing the stations in some 
special type of topography, and a depth was derived from the data for each group, namely, 
that depth for which the correction for topography and isostatic compensation would account 
for the mean observed free-air anomaly of the group. For group 1 it was 107 km., for group 
2 it was 124 km., and for groups 3 and 4 together 123 km.; the mean value was 118 km. 

If the free-air method of reduction is used, Helmert’s formula of 1901 should represent, on 
the average, gravity at stations in the interior, not in mountainous regions. But for stations 
in this class in the United States the average anomaly (free air) is +0.009 dyne. (See p. 67.) 
If the equatorial constant were increased to 978.039 to represent this class of stations 
better, the anomalies of the coast stations would be correspondingly reduced and the depths 
indicated would be: Group 1, 80 km.; group 2, 89 km.; groups 3 and 4 together, 78 km., 
with a mean of 83 km. Helmert’s 1915 formula indicates that gravity in the United States 
is slightly below normal, for according to the formula minimum gravity occurs in longitude 
107° west, and if allowance were made for this the previous correction of +0.009 dyne would 
be further increased and the resulting depth further diminished. A. rough estimate of the 
effect of using Helmert’s 1915 formula may be obtained by noting that according to it 

aSitzungsberichte der Koniglich Preussischen Akademie der Wissenscbaften, No. 41 (1915), p. 676, entitled “Neue Formeln fiir den Verlauf 

der Schwerkraft in Meeresnivoau beim Festlando.” 

6 Eneyclop&die der Mathematiscben Wissenscbaften Band VI IB, Heft. 2 Die Schwerkraft und die Massenvarteilung der Erde, p. 140. 





132 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


average gravity over the unit sphere is 0.016 d}me greater than according to his 1901 formula. 
If the anomalies in each group are diminished by 0.016 dyne, the depths implied are: Group 1, 
62 km.; group 2, 64 km.; groups 3 and 4 together, 46 km., making the mean 58 km., which is 
about the value found b}'' the various solutions for the United States, except the solution from 
the 56 stations in mountainous regions. This 58 km. by Helmert’s method is of course based 
on anomalies at coast (and probably largely Cenozoic) stations, which, as is indicated in other 
parts of this volume, are subject to systematic errors due to smaller densities than normal in 
the upper strata of the earth’s crust. While the value of 58 km. agrees well with the depth 
given for thd Coast and Geodetic Survey formula for 1916 for the United States, it should not 
necessarily be considered as being nearer the truth than the greater depths. 


Chapter IX.—SUMMARY. 


The group of publications of the Coast and Geodetic Survey dealing with deflections and 
gravity values shows that isostasy exists in a form nearly perfect in the United States as a whole, 
also that there is nearly perfect isostasy in areas which form comparatively small percentages of 
the area of the entire coimtry. 

The conclusions which may be drawn from the investigation reported in this volume sub¬ 
stantiate to a great extent the conclusions arrived at from previous investigations. This is an 
important fact, for 70 per cent more gravity stations in the United States were used at this time 
than in the preceding gravity investigation and many stations in Canada, India, and Europe, 
for which data were available, were also used. 

The depth of compensation was derived from the 216 stations in the United States and was 
found to be 60 km. When the stations were divided into different groups, other depths were 
obtained. They agreed in general with the value determined from all of the stations. An 
exception is in the case of the stations in mountainous regions, 56 in all. The values of the 
depth of compensation determined from these are 111 km. and 95 km. on two somewhat different 
assumptions. Owing to the fact that at stations in mountainous regions above the general level 
the values of gravity are very sensitive to a change in depth, it is believed that the value of the 
depth determined from the stations in mountainous regions has greater strength than the other 
values. 

The author believes that the best value for the depth of compensation is the mean of the 
Hayford value 0 of 97 km., which was obtained from deflection data at stations in mountainous 
regions and the value of 95 km. derived from gravity data at stations in mountainous regions. 
This mean is 96 km. The author believes that future values of the depth of compensation de¬ 
rived from much more extensive data will fall between 80 and 130 km. (See p. 112 and fig. 8.) 

For the United States there was found a decided relation between the sign of the Hayford 
gravity anomalies and the coast. The reason for this is explained in the following paragraphs. 
There was no relation found between the sign and the size of the Hayford anomalies and any 
other class of topography. There were found the usual relations between the elevations of the 
stations and the gravity anomalies based upon the Bouguer and the free air methods. (See 
p. 61 and figs. 13 and 14.) 

Decided relations were found in the United States and in India between the sign of the 
gravity anomalies and the Cenozoic geologic formation. The anomalies at stations located on 
this formation tend to be negative. In the United States a number of the Cenozoic stations are 
located on or very near the coast. As stated above, there appeared to be a relation between 
the gravity anomalies and the coast. This is probably explained by the presence of the very 
light material of the Cenozoic formations, which is present along nearly all the Atlantic and Gulf 
coasts of the United States. It seems probable that the negative anomalies at Cenozoic stations 
are in large part due to the presence of subnormal densities in the upper crust below sea level. 

There were found decided relations between the pre-Cambrian, Paleozoic, and Mesozoic for¬ 
mations and the sign of the gravity anomalies for the area of the United States. No very defi¬ 
nite relations were observed in Canada and in India. (See pp. 70-84.) 

It was found as a result of certain computations and investigations that local distribution 
of the compensation of a topographic feature is in general nearer the truth than regional dis¬ 
tribution of the compensation out to the outer limit of zone O (167 km.). It is not clear whether 
local distribution is more probable than the regional distribution out to the limit of zone M 
(59 km.). (See pp. 91 and 92.) 


a From A Supplemental Investigation in 1909 of the Figure of the Earth and Isostasy. 


133 







134 


IT. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


The difference in the anomalies at two stations which are close together horizontally, but 
which have a large difference in the elevations, seemed to indicate some error in the height 
formula used to compute the correction to gravity for the elevation of the station above sea 
level. A careful study of the matter showed no error in the formula, but it seemed to indicate 
that the difference in the anomalies could result from the combination of several causes no one 
of which could alone make the difference. (See pp. 93-96.) 

The best formula resulting from this investigation with which to obtain the theoretical value 
of gravity at any latitude in any part of the world was derived from 216 stations in the United 
States, 42 in Canada, 73 in India, and 17 in Europe, 348 stations in all. (See solution 8a, p. 127.) 
For each of these stations the reduction for topography and isostatic compensation had been 
made by the Havford method, using the same or very similar tables to those in Special Publi¬ 
cation No. 10. 

The formula is 

7 o = 978 039 (1+0.005294 sin 2 0-0.000007 sin 2 20) 

in which y 0 is the value of gravity sought and 0 is the latitude of the station. 

The first term of the formula is the theoretical value of gravity at the equator. From the 
constants of this formula was derived a value for the reciprocal of the flattening of the earth, 
which is 297.4. This value of the flattening is very close to other values recently derived from 
geodetic data in the United States and elsewhere. In the author’s opinion it may be considered 
as at least equal in strength to any other value derived from geodetic data. It is only 0.4 larger 
than Hayford’s best value from deflections, 297.0. It is only 0.8 less than Helmert’s value 
of 1901, and only 0.6 lower than the author’s value of 1912. It is only 0.7 larger than Hehnert’s 
value of 1915. 

The values of the terms in the other gravity formulas and for other depths of compensation 
are of interest and value as showing how conditions may be different in different parts of the 
country. The table of values shown on page 129 is remarkable in showing values which are so 
accordant although derived from data under different conditions and in different areas. 

If we assume that all the differences between the observed and computed values of gravity 
in the United States are due to errors in the assumed equatorial gravity and the depth of com¬ 
pensation, then the most probable gravity formula derived from data in this country alone is 

7o = 978.040 (1+0.005302 sin 2 0-0.000007 sin 2 20) 

and the derived depth of compensation is 60 km. The equatorial value of gravity in this 
formula agrees well with the world formula. It is from this formula that the 1916 Hayford 
anomalies were computed. 

From the various evidence it may be concluded that the average depth is probably greater 
than 60 km. As stated above, it is probably not far from being 96 km. 

The cause of the greater part of the anomalies is believed to be in general the deviation 
from normal in the densities in the upper crust probably not far below sea level. 

The study of the tables and maps accompanying this volume will convince one that in the 
regions considered the deviation of the earth’s crust from a state of perfect isostasy is slight, 
even for areas of comparatively small size. 

The evidence near Seattle, Wash., Minneapolis, Minn., and Washington, D. C., is conclusive 
that the cause of an anomaly is not regional in extent. If it were, the anomalies which are close 
together would not show such changes in sign and size. 

A problem presents itself to the geodesists of the world which can be easily solved. It is 
that each nation reduce its own gravity stations for topography and isostatic compensation by 
some rational method and publish the results. It will be well if the same system is employed 
by each nation, and to this end the International Geodetic Association will no doubt gladly lend 
its aid. If this work were done, the results would be of very great value to many branches of 
science. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


135 


BIBLIOGRAPHY. 

No claim to exhaustiveness is made for the following list of articles and passages in books 
and memoirs dealing with isostasy and related subjects. No attempt has been made to cover 
the more general field of articles treating of the constitution of the interior of the earth. 

The arrangement of articles is approximately chronological, according to the date of publi¬ 
cation. 

There were premonitions of the idea of isostasy long before it was definitely formulated. 
The French expedition to Peru observed latitudes north and south of Mount Chimborazo, and 
Bouguer ° expresses surprise at the small deflection of the vertical produced by the mountain, 
as compared with what he had been led to expect by his calculations from its size and density. 
He speculates on the possibility of cavities, but does not elaborate much on the subject. A 
more modern instance is that of Petit, who found the effect of the attraction of the Pyrenees on 
the latitude of Toulouse small but opposite in sign to what he had expected. * 6 * * Boscovich, 0 in 
attempting to explain the phenomena, approaches the modern idea rather more closely. Com¬ 
menting on Bouguer’s result, he expresses the opinion that the mountains are swellings caused 
by the earth’s internal heat. “If this be the case,” he says, 11 no matter is added there and the 
empty space within the vitals compensates all the visible matter that rears itself up into the 
mountain mass.” Probably examples of other premonitions could be gathered, but the subject 
passes beyond mere speculation only when some attempt is made to get a numerical estimate 
of the effects involved. Extensive calculation on the subject began with Archdeacon Pratt, 
whose name therefore heads the list. 

The name “isostasy” seems to have been proposed and first used by Maj. C. E. Dutton. 
(See list for 1889 under his name.) Lowthian Green has been referred to as an early advocate 
of the idea of isostasy. His book, “Vestiges of the Molten Globe,” London, 1873, is not availa¬ 
ble at this writing and references to it do not make plain whether he used the word “isostasy” 
or not. In any case Maj. Dutton seems to have coined the word independently. 

1855. 

J. H. Pratt, On the attraction of the Himalaya Mountains and of the elevated regions beyond upon the plumb-line in 
India, Philosophical Transactions of the Royal Society of London, vol. 145, p. 53. 

G. B. Airy, On the computation of the effect of the attraction of mountain masses as disturbing the apparent astro¬ 

nomical latitude of stations in geodetic surveys, Philosophical Transactions of the Royal Society of London, vol. 
145, p. 101. 

1859. 

J. H. Pratt, On the influence of the ocean on the plumb-line in India, Philosophical Transactions of the Royal 
Society of London, vol. 149, p. 779. 

-On the deflection of the plumb-line in India caused by the attraction of the Himalaya Mountains and of the 

elevated regions beyond; and its modification by the compensation effect of a deficiency of matter below the 
mountain mass. Philosophical Transactions of the Royal Society of London. Vol. 149, p. 745. 

1871 . 

J. H. Pratt, On the constitution of the solid crust of the earth, Philosophical Transactions of the Royal Society of 
London, vol. 161, p. 335. 

1880 . 

H. A. Faye, Sur la reduction des observations du pendule au niveau de la mer, Comptes Rendus, vol. 90, p. 1443. 

1881 . 

C. S. Peirce, On the deduction of the ellipticity of the earth from pendulum experiments, U. S. Coast and Geodetic 
Survey Report for 1881, Appendix 15. _ 

a Bouguer, La Figure de la Terre, d6termin6e par les observations de M. M. Bouguer et De La Condamine, etc. Paris, 1749, p. 364. 

6 Sur la densitd moyenne de la chalne des Pyr4n4es et sur la latitude de l’Observatoire de Toulouse; Comptes Rendus, vol. 29, 1849, p. 729. 

c Roger Joseph Boscovich, De Litteraria Expeditione per Pontificiam Ditionem, 1750, p. 475; quoted from Todhunter’s Mathematical Theories 

of Attraction and the Figure of the Earth, vol. 1, p.313. 







136 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


1882 . 

G. H. Darwin, On the stresses caused in the interior of the earth by the weight of continents and mountains. Philo¬ 

sophical Transactions of the Royal Society of London, vol. 173, pp. 187-230. 

1883 . 

H. A. Faye, Sur la reduction du barom&tre et du pendule au niveau de la mer, Comptes Rendus, vol. 90, p. 1259. 

1884 . 

F. R. Helmert, Die mathematischen und pliysikalischen Theorieen der lioheren Geodasie, Vol. II, chap. 4. 


1889 . 

G. K. Gilbert, The strength of the earth’s crust, Bulletin of the Geological Society, vol. 1, p. 25. 

C. E. Dutton, On some of the greater problems of physical geology, Bulletin Washington Philosophical Society, vol. 
11, pp. 51-64. 

R. S. Woodward, Mathematical theories of the earth, American Journal of Science, 3 ser., vol. 38, p. 351; also Science, 
N. S., vol. 1 , p. 194. 

O. Fisher, Physics of the earth’s crust, London and New York. 

W J McGee, The Gulf of Mexico as a measure of isostasv, American Journal of Science, 3 ser., vol. 44, pp. 177-192. 
Bailey Willis, Mechanics of Appalachian structure, Thirteenth Annual Report IT. S. Geological Survey, pp. 237-280. 

1894 . 

G. R. Putnam, Relative determinations of gravity with half-second pendulums and other gravity investigations with 
notes on geologic formations by G. K. Gilbert, U. S. Coast and Geodetic Survey Report for 1894, Appendix 1. 


1895 . 

G. R. Putnam, Results of transcontinental series of gravity measurements, Bulletin Washington Philosophical Society, 
vol. 13, p. 61. 

G. K. Gilbert, Notes on the gravity determinations reported by G. R. Putnam, Bulletin Washington Philosophical 
Society, vol. 13, p. 61. 

1896 . 

F. Leslie Ransome, The great valley of California: A criticism of the theory of isostasy, University of California, Bulle¬ 
tin of the Department of Geology. 

1900 . 

O. E. Schiotz, Results of the pendulum observations and some remarks on the constitution of the earth’s crust (The 
North polar expedition, 1893-1896, by Fridtjof Nansen), London. 


1902 . 


Adams, An experimental contribution to the question of the depth of the zone of flow in the earth’s crust, Journal of 
Geology, vol. 20, pp. 97-118. 


1903 . 


O. Hecker, Bestimmung der Schwerkraft auf dem Atlantischen Ozean sowie in Rio de Janeiro, Lissabon und 
Madrid. Veroffentlichung des Koniglich Preussischen geodatischen Institutes. Neue folge, No. 11. 

0. H. Tittmann, Geodetic Operations in the United States, 1900-1903, a report to the Fourteenth General Confer¬ 
ence of the International Geodetic Association, United States Coast and Geodetic Survey, 1903. 


1906 . 

J. F. Hayford, The geodetic evidence of isostasy with a consideration of depth of compensation and the bearing of 
the evidence upon some of the greater problems of geology, Proceedings of the Washington Academy of Sciences, 
vol. 8, p. 25. 

O. II. Tittmann and J. F. Hayford, Geodetic Operations in the United States, 1903-1906, a report to the Fifteenth 
General Conference of the International Geodetic Association, United States Coast and Geodetic Survey, 1906. 

1907 . 

J. F. Hayford, The earth a failing structure, Bulletin Washington Philosophical Society, Vol. 15, p. 57. 

O. E. Schiotz, Die Schwerkraft auf dem Meere langs dem Abfall der Ivontinente gegen die Tiefe. Christiania. 


1908 . 

F. R. Helmert, Unvolikommenheiten im Gleichgewichtszustande der Erdkruste, Sitzungsbericlite der Koniglich 
Preussischen Akademie der Wissenschaften, No. XLIV, p. 1058. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


137 


O. Hecker, Bestimmung der Scliwerkraft auf dem Indisclien und Grossen Ozean und an dereu Kiisten sowie 
erdmagnetische Messungen Zentralbureau der Internationalen Erdmessung. Neue folge der veroffentlich- 
ungen, No. 16. 

Laska, Ueber die Isostasie der Erdkruste. Oesterreichisclie Zeitscbrift fiir Vermessungswesen, Yol. VIII. 

1909 . 

O. Hecker, Die Schwerebestimmung an der Erdoberflache und ihre Bedeutung fiir die Ermittelung der Massen- 
verteilung in der Erdkruste. Zeitscbrift der Gesselschaft fiir Erdkunde. 1909, p. 361. 

F. 11. Helmert, Die Tiefe der Ausgleichsflacke bei der Prattschen Hypo these iiir das Gleichgewicht der Erdkruste 
und der Verlauf der Schwerstorung vom Innern der Kontinente und Ozeane nack dem Kiisten, Koniglich Preus- 
sischen Akademie der Wissenschaften No. XLVIII, p. 1192. 

J. F. Hayford, Figure of the earth and isostasy, from measurements in the United States, U. S. Coast and Geodetic 
Survey r . 

-. Supplementary investigation of the figure of the earth and isostasy, U. S. Coast and Geodetic Survey. 

O. H. Tittmann and J. F. Hayford, Geodetic Operations in the United States, 1906-1909, a report to the Sixteenth 
General Conference of the International Geodetic Association, United States Coast and Geodetic Survey, 1909. 

1910 . 

O. Hecker, Bestimmung der Schwerkraft auf dem Schwarzen Meere und an dessen Kuste sowie neue Ausgleichung 
der Schwerkraftsmes«»ungen auf dem Atlantischen, Indischen und Groszen Ozean. Zentralbureau der Interna¬ 
tionalen Erdmessung; neue folge der Veroffentlichungen, Nr. 20. 

J. F. Hayford and William Bowie, The effect of topography and iscstatic compensation upon the intensity of 
gravity, U. S. Coast and Geodetic Survey. 

Bailey Willis, What is terra firma? A review of current research in isostasy', Smithsonian Report, 1910. 

O. Z. Bianco, La Gravita alia Superficie del Mare e l’ipotesi di Pratt, Rivista Geografica Italiana, vol. 17. 

O. E. Schiotz, Uber die Reduktion von Pendelbeobachtungen auf den Meeresspiegel, Beitrage zur Geophysik, vol. 
10, p. 234. 

F. R. Helmert, Die Schwerkraft und die Massenverteilung der Erde, Ency'clopadie der Mathematischen Wissen¬ 

schaften, Band VI IB, Heft 2. 

L. de Marchi, La Teoria Elastica dell’ Isostasi Terrestre, Beitrage zur Geophysik, vol. 10, p. 177. 

Review of the figure of the earth and isostasy from measurements in the United States by J. F. Hayford. 1909, American 
Journal of Science, vol. 29. p. 193. 

Th. Niethammer and others, in the Proces Verbal de la 56 318 seance de la Commission Geod6sique Suisse. Neu- 
chatel, 1910, pp. 37-38 and 43-49. 

1911. 

J. F. Hayford. The relation of isostasy to geodesy, geophysics, and geology, Science, vol. 33, p. 199. 

O. Eggert, Review of the figure of the earth and isostasy from measurements in the United States, by J. F. Hayford, 

1909, Zeitschrift fiir Vermessungswesen. vol. 40, p. 534. 

Harmon Lewis, The theory of isostasy. Journal of Geology, vol. 19, p. 603. 

A. E. H. Love, Some problems of geodynamics. Cambridge, England. 

P. G. Nutting, Isostasy, oceanic precipitation, and the formation of mountain systems, Science, vol. 34, p. 453. 

H. F. Reid, Isostasy and mountain ranges, American Philosophical Society Proceedings, vol. 50, p. 414. 

Alfred Ruhl, Isostasie und Peneplain, Zeitschrift der Gesellschaft fiir Erdkunde, vol. 7, p. 479. 

M. P. Rudski, Physik der Erde. Leipsig. 

E. Kohlschutter, Uber den Bau der Erdkruste in Deutsch-Ostat'rika, Nachrichten von den Koniglichen Gesellschaft 
der Wissenschaften zu Gottingen. 

R. Schumann, Uber die Anwendung der Theorie vom Massenausgleich auf Vermessungen durch die Coast and Geodetic 
Survey der Vereingten Staaten, Oesterreichische Zeitschrift fiir Vermessungswesen. 

G. Cassinis, Sull’ Applicazione del Metodo lsostatico alia Riduzione delle Misure de Gravita, Rome. 

1912 . 

William Bowie, Effect of topography and isostatic compensation upon the intensity of gravity, second paper, U. S. 
Coast and Geodetic Survey. 

_ > Some results of the Hayford method of gravity reduction, Journal of Washington Academy of Sciences, vol. 2, 

p. 499. 

_ ; Some relations between gravity anomalies and geologic formations in the United States, American Journal of 

Science, 4th ser., vol. 33, p. 237. 

J. F. Hayford. Isostasy, a rejoinder to the article by Harmon Lewis, Journal of Geology, vol. 20, p. 562. 

Alfred Wegener, Die Entstehung der Kontinente, Petermanns Mitteilungen, vol. 58, pp. 185, 253, and 305. 





138 


17. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


L. V. King, Limiting strength of rocks under conditions of stress existing in the earth’s interior, Journal of Geology, 
vol. 20. 

H. L. Crosthwait, Investigation of the theory of isostasy in India, Survey of India, Professional paper No. 13. 

S. G. Burrard, The origin of the Himalaya Mountains, Survey of India, Professional paper No. 12. 

H. H. Hayden, The relationship of the Himalaya to the Indo-Gangetic Plain and the Indian Peninsula, Records of 
the Geological Survey of India, vol. 43, pt. 2. 

Lenox-Conyngham, Note in reply to Mr. Hayden’s paper on the relationship of the Himalaya to the Indo-Gangetic 
Plain and the Indian Peninsula, Records of the Survey of India, vol. 5, p. 161. 

G. R. Putnam, Condition of the earth’s crust, Science, vol. 36, p. 869. 

Adelbert Prey, Untersuchungen fiber die Isostasie in den Alpen auf Grund der Schweremessungen in Tirol. 

Sitzungsberechte der Kaiserlichen Akademie der Wissenschaften in Wein. Vol. CXXI, p. 2467. 

0. H. Tittmann, Geodetic Operations in the United States, 1909-1912, a report to the Seventeenth General Confer¬ 
ence of the International Geodetic Association, United States Coast and Geodetic Survey, 1912. 

F. R. Helmert, Die Erfahrungsgrundlagen der Lehre vom allegemeinen Gleichgewichtszustande der Massen der 

Erdkruste, Sitzungsberichte der Koniglich Preussischen Akademie der Wissenschaften, No. XX, p. 308. 

1913. 

H. Wolff, Die Schwerkraft auf dem Meere und die Hypothese von Pratt, Inaugural-Dissertation, University of 

Berlin. 

G. K. Gilbert, Interpretation of the anomalies of gravity, United States Geological Survey, Professional paper No. 85C. 

E. Hubner, Beitrag zur Theorie der Isostatischen Reduktion der Schwerebeschleunigungen, Beitrage zur Geo- 

physik, vol. 12, p. 588. 

S. G. Burrard, The mountains and their roots, Nature, vol. 91, p. 242. 

T. C. Chamberlin, Diastrophism and the formative process, Journal of Geology, vol. 21, p. 6, vol. 8, pp. 517, 523, 673. 
J. W. Spencer, Relationship between terrestrial gravity and observed earth movements of eastern America, American 

Journal of Science, vol. 35, p. 561. 

1914. 

William Bowie, Isostasy and the size and shape of the earth, Science, vol. 39, p. 697. 

-Isostasy in India, Journal of the Washington Academy of Sciences, vol. 4, p. 245. 

T. H. Holland, Isostasy, The Australian meeting of the British Association, Section C, Geology, Nature, vol. 94, p. 8. 
L. de Marchi, Come si formano le montagne, La Geografia, vol. 2, p. 161. 

Louis B. Stewart, The form and constitution of the earth, Journal of the Royal Astronomical Society of Canada, 
vol. 8, p. 1. 

Joseph Barrell, The strength of the earth’s crust, Journal of Geology, vol. 22 (series of articles continued in vol. 23) 

F. R. Helmert, Die isostatiche Reduction der Lotrichtungen, Sitzungsberichte der Koniglich Preussischen Akademie 

der Wissenschaften. No. XIV, p. 440. 

1915. 

H. J. Couchman, The pendulum operations in India and Burma, Survey of India, Professional paper No. 15. 

R. Schumann, Ueber die Anwendung der Theorie vom Massenausgleich, Oesterreichische Zeitschrift fur Vermessuugs- 

wesen (Zweiter Bericht), Vol. XIII. 

George F. Becker, Isostasy and radioactivity, Bulletin of the Geological Society of America, vol. 26, pp. 170-204, 
Science, vol. XLI, p. 157. 

T. C. Chamberlin, Harry Fielding Reid, J. F. Hayford, Symposium on the earth: Its figure, dimensions, and 
the constitution of the interior, American Philosophical Society Proceedings, vol. 54, p. 279. 

F. R. Helmert, Neue Formeln fur den Verlauf der Schwerkraft im Meeresniveau beim Festlande, Sitzungsberichte 
der Koniglich Preussischen Akademie der Wissenschaften No. XLI, p. 676. 

W. de Sitter, Isostasy, the moments of inertia and the compression of the earth, Koninklijke Akademie van Weten- 
schappen te Amsterdam, Proceedings of the section of sciences, vol. 17, pt. 2, p. 1295. 

Emile Belot, Le deficit et l’exc^s de la pesanteur sur les continents et les lies en rapport avec la condition isostatique 
de la croute terrestre, Comptes Rendus, vol. 161, p. 139. 

1916. 

C. F. Close, Gravity deflections in the Andes, Geographical Journal, vol. 47, p. 464. 

S. G. Burrard, The plains of northern India and their relationship to the Himalaya Mountains, Nature, vol. 97, p. 391. 
W. H. Hobbs, Assumptions involved in the doctrine of isostatic compensation, with a note on Hecker’s determina¬ 
tion of gravity at sea. Journal of Geology, Vol. XXIV, No. 7, p. 690. 



PART II.—SUMMARIES OF GRAVITY OBSERVATIONS AND 

DESCRIPTIONS OF STATIONS. 


& 

CHAPTER I.—ABSTRACTS OF RESULTS. 

In this part of the volume are given the abstracts of the observations made at the base 
station in the office of the United States Coast and Geodetic Survey at Washington, D. C., and 
at the field stations in the United States established in 1909 and later years, for which similar 
data have not already been published in the various reports of the Survey. There are also 
given the descriptions of all the stations. 

An index on page 187 gives the names of the stations and the pages of the various publica¬ 
tions in which gravity data may be found. 

STANDARDIZATION OF THE PENDULUMS AND METHODS OF OBSERVING USED IN THE FIELD. 

As is stated on page 49, the pendulums were standardized at the Washington station 
before and after a field season or between two seasons which were not long separated in time. 

Usually the mean of the two values of the periods of a pendulum determined at the base 
station before and after a season’s field work was used in the determination of the relative 
intensity of gravity at the field stations. An exception to this general rule occurred when it 
was found, after the season extending from June to December, 1909, that the periods of the 
pendulums had been affected between standardizations by a film of foreign substance, which 
had accumulated on the agate planes of the pendulums. Upon the removal of the film the 
pendulums resumed nearly their former Washington periods. (See p. 141.) 

Beginning with the standardization of the pendulums in 1912, each of the pendulums had 
its period determined each time by swinging it continuously between consecutive determina¬ 
tions of the chronometer corrections. This plan has been followed since that time, both at 
the base station and in the field in establishing new stations. The previous custom had been 
to swing all of the pendulums of a set during the interval between two determinations of 
the chronometer corrections. It was only occasionally that more than two determinations of 
the chronometer corrections were made at a station. 

Each of the pendulums of a set is now swung for at least 24 hours in three periods of 8 
hours each, whffe previously each pendulum was swung for only 16 hours at a station in two 
periods of 8 hours each unless unfavorable weather prevented time observations on the stars 
at the end of the 48-hour period. In the earlier work the variation in the rate of the chronom¬ 
eters would occasionally make a large range in the values of the gravity at a station determined 
by the separate pendulums, but the mean of all the values was free from the effect of change 
in rate. 

In the present method, where the period of a pendulum is obtained from separate time 
determinations, the result for any one pendulum is not affected by variation in the rate of the 
chronometers. 

ABSTRACTS OF RESULTS. 

In the table on pages 144-176 are given the pendulum observations and reductions for the 
stations in the United States which were determined in 1909 and later years. Similar data 
for the stations established before that year are given in other publications of the Survey, 

139 


140 


TJ. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


which arc indicated in the index on page 187. The number of a station is the same as was 
used in the various tables and the discussion in Part I of this volume. (See especially the 
table on pp. 50-52.) 

The tables need little explanation. Under the heading “Total arc” are given the values 
of the arc through which the pendulum oscillates at the beginning and at the end of a period 
which is usually about 8 hours long. The period given has been corrected to reduce to an 
infinitesimally small arc. 

The standard temperature is 15° C., and a correction is applied to the period for any devia¬ 
tion of the observed from the standard temperature. The standard pressure of the air in the 
pendulum case is 60 mm. of mercury. A correction must also be applied for deviations of the 
pressure from the standard. 

Finally there is the correction for flexure. This is necessary because the force of the 
pendulum in motion makes a sympathetic swinging of the pendulum case and its support, 
and this in turn reacts on the pendulum and affects its period. The flexure is determined by 
means of the interferometer, which is described in Appendix 6 of the Report for 1910. The 
flexure of the case and its support makes the period too long, and consequently the correction 
necessary to reduce the period to what it would have been in a rigid structure is negative. 

It will be noticed that the period of a pendulum is determined by its comparison with each 
of two chronometers. This is done to avoid mistakes and to make the effect of accidental 
errors smaller. 

The coincidence interval, as its name suggests, is the time which elapses between two 
consecutive coincidences between the beat of the chronometer and the swing of the pendulum. 

The pendulums were swung in the direct position in all cases, both at the base stations and 
in the field. This fact is indicated in column 3 of the tables. The pendulums are designated 
as A4, A5, and A6 in one set and B4, B5, and B6 in the other. The pendulums used are indi¬ 
cated in the second column. 

The tables do not state whether there were local time observations or comparisons of the 
chronometers with the noon signals sent out from the Naval Observatory over the commercial 
telegraph lines (The Western Union and Postal Telegraph Companies). It is evident, however, 
from the data in the columns of corrections for rate that there was such a determination between 
the two swings where a change in the rate corrections occurs. If the rate corrections at a sta¬ 
tion are the same for each swing, then there were only two determinations of the chronometer 
corrections at that station, one at the beginning and the other at the end of the entire set of 
observations, as it is quite unlikely that the computed rates during two intervals between 
three different time comparisons would come out exactly identical. 

During the first season of 1909, the season of 1914, and the first season of 1915 pendulum 
B4 showed great changes in its period. Careful inspection of the pendulum failed to discover 
any cause for this. It was finally decided to strengthen by an additional rivet the connection 
between the stem and the bob; after this was done no further trouble occurred. 

There is given below a summary of the periods at the base station of the six United States 
Coast and Geodetic Survey pendulums. These periods were used in computing the relative 
intensity of gravity at the field stations. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 141 

Summary of periods of pendulums resulting from standardizations at the base station, Coast and Geodetic Survey Office, 

Washington, D. C. 


Date 



Mean periods 



Observer 


A 4 

A 5 

A6 

B4 

B5 

B6 


January, 1909. 

0. 5008393 

0.5006615 

0.5006240 

0.5008091 

0. 5007230 

0.5007031 

W. H. Burger 

June, 1909. 

. 500X368 

.5006612 

5006951 

. 5008229 

. 5007212 

.5007036 

T)n 

November, 1909. 

.5008320 

.5006561 

.5006208 

Do 

December,'1909. 

.5008362 

.5006595 

a. 5006248 

. 5008257 

.5007226 

. 5007040 

l)o! 

Do. 

.5008363 

.5006592 

a. 5006234 




Do 

May, 1910. 

. 5008353 

.5006588 

.5006233 




Do. 

October, 1910. 

. 5008348 

.5006602 

.5006257 

.5008246 

. 5007220 

.5007016 

H. D. King. 

June, 1911. 

. 5008374 

.5006618 

a. 5006265 





Do. 

. 5008360 

. 5006622 

a. 5006289 




Do 

January, 1912. 

. 5008392 

. 5006635 

. 5006286 

.5008126 

. 5007232 

. 5007042 

Do. 

July, 1914. 

. 5008377 

. 5006623 

5.5006287 

.5008117 

.5007225 

b. 5007026 

CX.Garnerand 








J. D. Powell. 

Do. 

. 5008385 

. 5006639 

c. 5006272 

. 5008119 

.5007228 

c. 5007020 

Do. 

January, 1915. 

.5008373 

. 5006629 

. 5006288 

.5008178 

.5007210 

.5007023 

Do. 

July,1915. 

. 5008379 

. 5006629 

. 5006278 

. 5008289 

.5007207 

.5007013 

Do. 

January, 1916. 

.5008392 

. 5006639 

. 5006301 

. 500S292 

. 5007209 

.5007014 

Do. 

Mean. 

.5008369 

. 5006613 

. 5006262 


. 5007219 

.5007026 







a The mean was used. 

& Rate corrections were determined from star observations. 

c Rate corrections were determined from the noon signals sent by telegraph from the Naval Observatory at Washington, T). C. 


During the second season of 1909, mentioned on page 139, in which the periods of the 
pendulums were affected by films of foreign substance on the agate planes on which the 
pendulums swing, W. H. Burger established the following stations in the order given. The 
table show r s which stations were reoccupied, the name of the second observer, and the value 
of gravity adopted. 


Number and name of station 

Reoceupied in 
1910 or 1911 by— 

Adopted 
value of 
gravity 

Number and name of station 

Reoccupied in 
1910 or 1911 by— 

Adopted 
value of 
gravity 

102. Cloudland, Tenn. 



88. Wilson, N. Y. 



103. Hughes, Tenn. 

T. L. Warner. 

979.553 

89. Alpena, Mich. 

. 


106. Fort Kent, Me. 



57. Iron River, Mich. 

H. D. King._ 

980.633 

85. North Hero, Vt. 

H. D. King. 

980.588 

58. Ely, Minn '. 


86. Lake Placid, N. Y. 






87. Potsdam, N. Y. 



60. Mitchell, S. Dak. 










In order to strengthen the field w r ork, stations Hughes, North Hero, and Iron River were 
reoccupied as is indicated in the above table. The King and Warner values were adopted for 
North Hero and Hughes, respectively. The Burger value for Iron River when the November 
4 to 10, 1909, Washington periods were used differed only 0.006 from King’s value. The mean 
of the two determinations for that station was adopted. The November 4 to 10, 1909, Wash¬ 
ington periods were also used in computing the value of gravity at Ely, Pembina, and Mitchell. 
(See p. 87 of Special Publication No. 10). 

For Cloudland the Washington periods of November 4 to 10, 1909, and Warner’s periods 
at station Hughes were used as standard values. North Hero and Iron River, with their 
adopted values of gravity, were used as the base stations for Lake Placid, Potsdam, Wilson, 
and Alpena. Hughes and North Hero, with their adopted values of gravity, were used as 
bases in determining the value of gravity at Fort Kent. 

From July, 1914, until January, 1916, the chronometer corrections at the base stations 
and at field stations were obtained from comparisons with the noon signals sent over the 
lines of the Western Union and the Postal Telegraph companies from the Naval Observatory 
at Washington. At the beginning of each month the corrections to the time as sent out by 
the observatory were furnished for each day of the preceding month. These corrections were 
seldom greater than 0.10 second. Before the year 1914 the chronometer rates were deter¬ 
mined by the gravity parties from local time observations on the stars with an astronomic 
transit. 












































































142 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


The tests at the base station and at field stations showed that the time by telegraph gave 
as satisfactory results as the time determined by local astronomic observations. Of course 
there were errors in the absolute time as received at a field station over the telegraph wires due 
to the time of transmission, but this error was probably very nearly the same for each day at a 
station, and the effects on the rate determinations of the chronometers were not appreciable. 

In the table on page 141 there are given the results of two standardizations in July, 1914, 
one with local time and the other with time from the observatory. The two results agree closely. 

There are given below the values of the gravity at three stations at which both local and 
Naval Observatory time was used in rating the chronometers. The values indicate that the 
observatory time by telegraph is satisfactory. 


Name of station 

Observer 

Date 

Time used 

Observed 

gravity 


JH. D. King. 

1911 

1914 

1911 

1914 

1896 

1914 

Local time. 

979.346 
979.345 

980.343 

980.344 
979. 720 
979. 728 

Albanv N Y 

1C. L. Gamer. 

/T. L. Warner. 

Noon signals. 

Local time. 


\C. L. Garner. 

fG. R. Putnam. 

Noon signals. 

Local time. 


\J. D. Powell. 

Noon signals. 


The use of the observatory time materially lessens the work and the cost of establishing 
a gravity station. 

There is given below a table which shows the chronometer rates at stations near and at others 
which are distant from Washington. These rates were determined from the comparisons with 
the Naval Observatory time received by telegraph. The range in the daily rates at the distant 
stations is about the same as the range for the near ones. As there are two chronometers, it 
can be seen whether the rates are due to errors in the time signals or to conditions not connected 
with those signals. For instance, when the rate for one day is considerably lower by both 
chronometers than for the other two days it is probable that this is due to the time signals. 
This might be the case for the first 24-hour period at station 194 (Huntley, Mont.). This is 
also the case for the first interval at station 202 (Moorcroft, Wyo.). Here the error was of 
such size that the observer swung his pendulums a fourth day. On the other hand, at station 
192 (Poplar, Mont.) the third day gives a low rate for one chronometer and a normal rate for 
the other, and the cause of the variation of the first could not have been an error in the time 
signals. 

The chronometers are subject to the temperature changes which occur in the pendulum 
room, which no doubt cause variations in the rates, but, as the pendulums are sw un g almost 
continuously for the interval between the determinations of the chronometer corrections, no 
appreciable errors enter into the mean period for a pendulum from the variation in rate. 



























INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


143 


Chronometer rates. 

STATIONS NEAR WASHINGTON (MAXIMUM DISTANCE 800 KM.). 




Daily rates 



Daily rates 

Number and name of station 

Date, 1915 

Chro¬ 
nometer 
No. 1823 

Chro¬ 
nometer 
No. 1841 

Number and name of station 

Date, 1915 

Chro¬ 
nometer 
No. 1823 

Chro¬ 
nometer 
No. 1841 

146. Richmond, Va. 

Feb. 9-10. 

Seconds 

-3.89 

Seconds 

-2.07 

155. Knoxville, Tenn. 

May 10-12. 

Seconds 
-3.47 

Seconds 

-3.23 


Feb. 10-11. 

-3.78 

-2.07 


May 12-13. 

-3.71 

-3.40 

147 Emporia, Va. 

Feb. 11-12. 

Feb. 24-25. 

-3.99 

-2.87 

-2.27 

-2.18 

156, Bristol, Va. 

May 13-14. 

Ma}' 19-20. 

-3.45 

-3.92 

-3.36 
-3.58 


Feb. 25-26. 

-2.28 

-1.82 


May 20-21. 

-3.80 

-3.61 

148. (ireenville, N. C._ 

Mar. 9-10. 

-3.85 

-2.82 


Mav 21-22. 

-3. 56 

-3.42 


Mar. 10-11. 

-2.97 

209. Laurel, Md. 

Nov. 18-19_ 

-2.19 

+3.08 


Mar. 11-12. 

-3.89 

-2.86 


Nov. 19-21.... 

-2.24 

+3.45 

149 Wilmington, N. C. 

Mar. 16-17. 

-3.81 

-2.88 


Nov. 21-22_ 

-2.34 

+3.55 


Mar. 17-18. 

—3.56 

-2.63 

212. Rockville, Md. 

Nov. 27-28_ 

— 1.51 

+2. 55 


Mar. 18-19. 

-3.66 

-2.63 


Nov. 28-29.... 

-1. 68 

-i-2.35 

150. Cheraw, S. C. 

Mar. 25-26. 

-3.73 

-2.89 


Nov. 29-30.... 

-2.20 

+2.46 


Mar. 26-27. 

—3.84 

—3.15 

214. Fairfax, Va. 

Dec. 3-4. 

+0.27 
+0.45 
+0.66 

+3.20 


Mar. 29-30. . 

-3.46 

-2.92 


Dec. 4-5. 

+3.34 

Ini Charlotte, N. C.. 

Apr. 5-6. 

-2.65 

-1.87 


Dec. 5-6. 

+3.40 



—2.64 

-2.05 

213. Upper Marlboro, Md. 

Dec. 11-12. 

+2.26 

+3.41 


Apr. 7-8. 

-2.26 

-2.06 


Dec. 12-13. 

+ 1.52 

+3.72 

154 Winston-Salem, N. C _ 

Apr. 12-i3. 

-3.38 

-2.73 


Doc. 13-14. 

+1.01 

+3.86 


Apr. 13-14. 

Apr. 14-15. 

\pr. 22-23. 

-3.54 
-3.55 
-4.02 

-3.10 
-2.93 
-3.21 

219. Hagerstown, Md. 

1916. 

Jan. 8-9. 

-1.92 

+3.35 


Apr. 23-24 

—4.14 

-3.36 


Jan. 9-10. 

-1.65 

+3.38 

153. Cleveland, Term. 

Apr. 24-26. 

Apr. 30-May 1. 

May 1-2. 

May 2-3. 

-3.97 
-3.88 
-3.86 
-3.75 

-3.32 
-3.09 
-3.04 
-3.12 


Jan. 10-11. 

-2.09 

+3.57 


STATIONS DISTANT FROM WASHINGTON (MAXIMUM DISTANCE 2700 KM.: MINIMUM DISTANCE 1400 KM.). 


Daily rates 


Number and name of station 

Date, 1915 

Chro¬ 
nometer 
No. 1828 

Chro¬ 
nometer 
No. 1838 


Aug. 5-6. 

Seconds 

-2.10 

Seconds 
+8.14 


Aug. 6-7. 

-2.21 

4-8.26 


Aug. 7-8. 

-2.14 

+ 8.34 

187. Faith, S. Dak. 

Aug. 12-13_ 

-2.18 

+6.62 


Aug. 13-14_ 

-2.24 

+ 7.24 


Aug. 14-15_ 

-1.90 

+7.48 

189. Towner, N. Dak. 

Aug. 20-21.... 

-1.61 

+7.87 


Aug. 21-23_ 

-1.50 

+7.63 


Aug. 23-24_ 

-1.91 

+6.22 

190. Crosby, N. Dak. 

Aug. 27-28.... 

-1.94 

+3.61 

Aug. 28-29_ 

-1.62 

+5.25 


Aug. 29-30- 

-1.86 

+4.97 



-1.75 

+5.74 


Sept. 3-4. 

-1.37 

+5.68 


Sept. 4-5. 

-1.01 

+5.78 

188. Marmarth, N. Dak. 

Sept. 10-12.... 

-0.80 

+4.25 


Sept.12-13.... 

-1.10 

+4.99 


Sept. 13-14_ 

-1.12 

+5. 26 

193. Miles City, Mont. 

Sept. 17-18.... 

-1.01 

+ 1.44 

Sept. 18-19_ 

-1.18 

+ 1.63 


Sept. 19-20.... 

-1.62 

+1.29 

194. Huntley, Mont. 

Sept. 22-23.... 

-0.13 

+ 1.08 

Sept. 23-24_ 

-0.39 

+1.36 


Sept. 24-25_ 

-0.66 

+ 1.47 




Daily rates 

Number and name of station 

Date, 1915 

Chro¬ 
nometer 
No. 1828 

Chro¬ 
nometer 
No. 1838 

195. Lander, Wyo. 

Sept. 29-30_ 

Seconds 

-2.31 

Seconds 
+2.17 

Sept 30-Oct. 1. 

-2.33 

+2.18 


Oct. 1-2. 

-2.17 

+2.13 

198 Edgemont, S. Dak. 

Oct. 5-7. 

-1.74 

+2.18 

+2.67 


Oct. 7-8. 

-1.83 


Oct. 8-9. 

-2.01 

+2.36 

202 Moorcroft, Wvo. 

Oct. 12-13. 

0.00 

+4.12 


Oct. 13-14. 

-1.40 

+2.84 


Oct. 14-15. 

-0.74 

+3.31 


Oct. 15-16- 

-1.01 

+3.26 

201 Wasta, S. Dak. 

Oct. 20-21. 

-1.00 

+2.48 


Oct. 21-22. 

-1.16 

+2.25 


Oct. 22-23. 

-1.19 

+2.08 

206 Valentine, Nebr. 

Oct. 26-27. 

-1.85 

+3.36 
+3.26 


Oct. 27-28. 

-1.88 


Oct. 28-29. 

-1.91 

+3.01 

205. Randolph, Nebr. 

Nov. 2-3. 

Nov. 3-4. 

-1.46 
-1.62 

+2.13 
+2.35 


Nov. 4-5. 

-1.42 

+2.31 

208. Leon, Iowa. 

Nov. 10-11_ 

-3.27 

+3.56 


Nov. 11-12.... 

-3.38 

+3.56 


Nov. 12-13_ 

-2.95 

+3.22 























































































































































144 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


© 

a 




ss 

C) 


© 

p 


a 

03 

© 


<®005NOO)UU05NHHCHN'HC«:'fMTt‘iOW 
'**<'«*<CO-*<cOCOCOCOCOCOCOCQCOCDCDcDcDcOC^(NCNe3C'5<N 
• 00 00 OC OC '/ O) X' CO cr.. (X X 00 C O © © '^ © © © © © © 

’gggggggggggggggggggggggg 

*0 lO kO >0 ‘O *0 lO M? lO »0 lO lO to 1C lO iO lO >0 'O ‘O O O lO 


Xl^Tf(NOcOCOO!NTfCC 
Cl 05 O O C M' 05 CO- 

““ ■ ^ggs 55 


__ W-<05 

O C/5 1 

_ ^ 

-.GOCOOOCOCOOCGCCOXOCt^t^r-- _ - - - 

OOOOOOQOOOOOOOOQOOQ 

oocoooooooooooooooo 

_ _ _ - _ - _ - _ _ - - LO lO LO “ ~ 


CCOOOCO't'^O'O 

eo c? oo r 


.dOOOOOO 

tHtH r- tH 1 - 

- 0000 


»0 lO *0 lO lO ‘O lO 10 lO lO 1.0 


So 

°.-A% 

pfe* 


5CCCCCCC5©OCCONOOrfOt^OJair'NtOHM 
- < CTM^ Oi VO l- G- t- O CS O <N CO CO ”»*< <M ^ »p CO 

- ^O-^KOGOMNIMNOPN 


O Tf TT t)( cr CO CC C'? CO W M CO G G G O G G IN M 03 N (N IN O 

• co co co co oo co oc co oo go co co cd cd o e o o o o g c g o co 

•=950 55 q § goo § ooggooco gg oco o 

: 10 o to ic *o 10 >c to >0 0 <0 'O >010 >0 ic «o <o 


gg^ 


5WONC 
' < CO c 

1 OS c 


) rH ONOON» 

) CO C- - 

I cs c 


_ _ ..NCOQOCOCr.OCOC. . 

O*—<»—<OCOOOOOC<MC^(NC___ 

_^<>DoooC(Xc/jGOODa;oooccct^i^.t^r^i^r^t^r^t^-t>-t'^t>- 

gggggggggggggggggggggggg 

“ “ iCiCiOiOiCiCiCiC'OiCiCiCiOiOiCiCiOiOiCiOiOiO 


1 

fl 



0 



ID 

rH 

lO 

03 

1C 

(M 

CO C 

D1 

0 

c 

z 

fO 

c? 

i 

.•CO 

5; 

0 

CO 

GO 

O 

00 

£h 

CO 

CO 

00 

s 

<d 

/ 

00 

r: 

00 

tH Cl 

35$ 

tH 

CO 

00 

c 


X 

00 O 
O 

x 

O 

O 


X 

0 

0 

X 

X 

0 

0 

HX 

X 

rfl 



lO 

»o 

»o 

•G 

IO 

0 


lO 

0 

LO lO 

ID 

O 

* 


O 












5 10 o 00 CO 10 CO 


©OO^MOONCOCCCO 

C050050Nt>.05«OC 

r-tO^Ol-HOOOOO 

00(^00 00 00 00 00 00 - 


OOU5CNCOOOOOCOH(MO*0 
.OJOJiC^lN^HrmNCOCOCOiOO 
5COC4MNNNMOOOOOO 
) 00 z/i t - 1 ^ p- 1 ^-1> 

jgggggggggggr 


iQ 1 C lO 10 lO lO lO lO »C 1 C 1 C 10 1 C 1 C IC LC 1-0 10 1 C I-C >C lO lO 1 


s 

o 

•<s* 

ho 

•§ 

?» 

Co 

§ 

o 

-SO 

<s 

CO 

© 

r* 

§ 

rS 

•§ 

§ 

Oh 


o 

3 

d 

-f-> 

© 


72 

o 

X2 


73 

fl 

CO 

C/3 

to 

a 

*3 

c3 


X 

O 

.Q 

.9 

.fl 

H-» 

O 

& 

© 

a 


O 

-Q 


fl 

£ 

O 

XI 

co 

© 

h 

c3 

co 

© 

-Q 

a 

§ 

a 


a 

o 

fl 

o 

(h 

-fl 

o 


c3 

a 

© 

44 


© 

% 


a 

o 


o 

O 


fl 


S © 

.© ^ 

£ S ® oH 

Oif!7G0 

o o 


6'. .« 
H 0 »ON 

gg^z® 


Jl ® 

® t. 

B 
Ph « 


I I I I I I I 1 I M I I I I I I I I I I I I I 

NNINNNNOfflOOOCNMCOMMWO^ffigag 


[ I I I I I I I I I I I I I I I I I I I I I 1 I 

NC<ia<(NCi(NtD«oocootOMrocoMeo«05g>oig5055: 


OOODOCOOOOOO<NINC'1«C^(NIM(NC^IMC^C^050>01050>05 


+ + + + + + + + + + + + + + + + + + -(: + + I 


(tOiMOooaS'niMoct'toiraaii-itcus^iNrtrt 


+ + + + 


a « % 

® fe 3 
E- 1 &-*■ 


<03e200r-«500O3CD00C0Ot~OC»''f'*t<O 

2I^CDCC'^eOCOCi^CD0000050005t't^t^Crj 


>t^c<iTfiT^corocococo-^io^»c^oc 


o 

*H 

< 


CNH00000050C««05 0C’0000©00003030005P» COOOOtsNCOOOGOGOOOHO)COaHOHOHh.OO 
rH rH rH rH rH rH rH rH rH r-i r —1 rH iH rH rH rH H rH rH rH 

I I I II ! I I I I I I I I I I I I I I I I I ! I I I I I I I I I I I I I I I I I I I I I I I I 


'fl 

© 


c 

c 

fl 

fl 


© 

Ph 


a 0 

§*3 

o *={00 

o * 



iOiO©NNOilOlOO©eC^M©' 

00 CO CO 00 GC 00 CO CD CD CD CD CD C© CO CO CO CD CO 
©OOOOOOOOQQOOQQOQO 

000000000000000000 

iO iO LO IQ lO lO lO *0 lO lO lO ‘O lO iO >C lO 10 *o 


rH CD 
CO o 
O - 
K 




gggggggggggggggggggggggg 

5 1C 10 lO 10 10 10 lO 10 10 lO lOO 10 lO 10 ic 10 10 »C 10 10 10 10 


a 6^ 

c z w 
05 -cc 
S3 ^ 

S 03 


WCCKNOl . . . . _ . . .. . . . . 

OJWOOJrHHHH^MHMMCOCOCCWO 
00 CO G© 00 CO 00 00 00 00 00 00 CO CO O CO CO CD CD 

S oooooocfloooooooooo 
00000000000000000 
l': 1.010 o 101010 >o »o 10 *o ic io ic lo io o ic 



_)ODC- 

1^ U X X' I- N N I' N N N N N C X 1 G O G O CD G G CC O 
OOOOOOOOOOOOOOOOOOOOOOOO 

S OOOOOOOOOOOOOOOOOOOOOOO 
lO 10 O iO iO iO >o o iO 1C iO lO iO 'O iO iO 1010 »o *o o 10 


JH fl 
Ph «5 


s'2? 
£ 


CHMCO^CODOCW^OOiOOOCQOW^COCOrHOq-f 
»0 lO lO 10 lO ‘O 10 lO '<D >C lO 10 >0 lO G G G lO lO 10 X G G 


S 2 £ 
®Ss 
H o.« 


. .CCDDliDC0CDCDCDi--C00CiCD00CDC0r-'l-CDC^CDC s a-J < ^O 
^MOOCOMOHXHOlTfCGOlOiOiO^GCOHNWH 


o COMMMNNhOhOhhOOhCOOWWMMMCO 

i-H •—t I-H r—i r—t rH rH rH T-H rH rH rH rH rH rH rH rH rH i-H rH rH rH r—< rH 


OCOOCC-=J*D403C 
cc co eo cc co co h 1 


' cu N CO U N G O0 OJ N ^ r)i !C 10 G G 
hhhhhhhhcOCOCOCCCOCO 


c3 

'rt 

-*H 

o 


03 

.9 


gO©HO©»ODODiO , tt>'iOh.CC>©©OiOCOCONt>.N 

^HH NCIHHHNHHC^HHhHHHMHHHHHH 


OiOOOOlMTj'DODOCON^aciOOXCONDDDS^ 

HhHHHHHC^HNHHHHHHHNHHHHHH 


at 


iGMONONGHHTfHCONNr 


<00>CCNOiOOO 


^i0^ii3i0^i0T)5*l3oi.0»0i0H<i0L0i0i0i0'^i0^'.0i0'^ 


h»NCOOCOiHX05Tj<DM»Ot>.NXHDONCOOO(NNH 

> <j5'^iLCl£5Hj*lDH|5^Tl5Hj5'^5kOHl!lf5^ilOTl5kOlClO^U5Tj<»0 


©rH 

fl 03 
© > 

*© 3 

fl 

*0 

o 


A iOH 

" O u® 

U C ®H 


NiONC^iJ'iOCONNiNOiOiCiCOGOCiCNO^CJcOX^ 

«ooOOOrHCNi'^ 5, ^ 3 cococo'«i5cDiot^cO'>i 3 LCo©rPrPcD»ot>I 
OOOOOOOCOOOOCOOOGOCOCOOC-OOOOOO 

COCOCOCOCOCOCOCCCCCCCCCOCOCOCOCOCOCO'^Tji'^^ti'rjiT^ 


S NMOOX^fNMMGiONNOOOX^HOWNCO 
XOOO^HTf TpOWN'CtOCMOI-XOGTHC'lCG 

ddccoOHtNioicioiOH-’ xrd Hcowciojocidoioioi 
rH rH OOhhhhhhhhiOiC<OiOiO»OCiCGiCiO»0 
CCCOOOCOCOC'OCOCOCOCOCOCCCCCOCOCOCOCOCOCOCOCCCOOO 


A i Of) 

||5| 

O C © H 


DNHOMU3C 


j H (N N C4 © Tj< D c 


«0 (N CO rf IO X X © N N X IN N IO CC (N H H o C 

OOOOOO O' OOOOOO OOG5 OOrHrHrHr- C 
COCOCOCOCOCOCOCOCOCOCOCOCOCOCOCCCOCO'^'^'^^' 


CO-^r _ _ _ _ . _ . _ _ . 

HrHHHrHrHHHrHHHHlOlO*OlO»—__— 

cocococoeococococococococccococococoeocoeocccoco 


c3 

p 


o 

I #»»*•••••#«• Ifll 

00 ^r’ «!J 22 ..lO©©©t^N — . 

gWC0 05 05HH rtNNNrtcOHHHHHHNN 

rH © © © © d ci 


op 

. -I- . , 01 

- O tH tH CO 00 


CvJ c4 00 00 o o 


• • -7 

OO I . I . . •lOCDCDrHtHtHcitHlHl'LQOOO 

HH HN(NNW«HHHHHHWN(N(N(NN 


g555S©flflCflflflflflflflflflflflflflOfl 

XXXXXX&eicicicZaSacZGicicS&cZcZGSaiGZc: 

nWpHMHHH5hh?H>rsHH>I-?Hs t—jt—jHjhjH5 


ScSocSdfiddflgdBoriddflBBHOH 

— — — - - - N a3<3^c3c3©c3c3c3cJcCc3c3c3c3c3o3c3 


o.g 




fiflfifififiOflOQClOOPOflfififiOfiQQQ fififiPPfifiOOPPflPflPQPPQPPfifiO 


SdS 

pi~5 


'»t <- ^^'*r'^TH'^-»t | -^Tt<-^'^»0*0‘0L0lCL0«DcDcDcDCDO 


TTTt‘ifTjlTfTj<rt''rt<rt'rtl-rJHrtlLOAClOlOVDlOCDCDCDOCDCD 

WW«cppQp;pQpq«(ri«fl:pqpqpqpqpQpqpPPPPP 


to 

.So 

CO 


H(NCC^©©l--XDOHNCC^©©NXDO^(NCC'<J< 

hhhhHhhhhhMNNNCS 


fe 

© 

C /3 

ja 

o 

'fl 

a 

03 

fl 

•9 

rt 

-*-» 

in 


ro^ 

«|s| 
- e & 

B-goK 

|31s 

Is 


o^r 
-§t? . 

«s®a 
o ,2 “ 

- SB s 
fl *fl r cp 

, ©^ 


r4 -W —’ 

safcs 

4 033 

,® O r/3 3= 














































































































10588 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


14 


© 


©© 


S 8 

to 01 

S 8 

c^co 

38 

gg 

O 

CO O 

050 

050 

e® 

05 

05 O 

05 O 


S-H 

fe-H 

S-H 


© o 
S-H 


^ s H t ^3 
rO M cm in co 


© © © © © © 
f - I- t- t-f-i- 
© © © © © © 


M f-5 W N !N C 


© © © © © © 
f- b- r>- t ~ 


M O W CO N 
HMHhNtT 
CO CO CO CO CO CO 

©©©©©© 
r - r- r'- 
DClD © © © 


Cl rt ih -r C C 

W M- CO " »0 
to to »0 to to IQ 

OiClOCiOJOJ 

t> F. F- 

05 © © 05 © w5 


rr©©t^©rrr^i-4corrt'»iorroo© 

t- -r N N c t- O N 05 OG C/j C~: CC tO t'" 

ooooooooooooooo 

05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 

F- t"-r- r- i-- f'- r-~ 

©©©©©©©©©©©©©©© 


ICOHONH 

S ^p vretHd 
( 0000(0 

05 05 05 © 05 O 
05 05 05 C5 05 05 


05 05 05 05 05 05 
r- i- r~, 

05 05 © 05 05 C5 


05 05 05 05 05 05 
r'- i- i- t~- 
05 05 05 05 05 05 


HMNU5ICO 

■»?CO«Cl-HH 

t- c- 

05 05 05 05 05 05 

i - r- r^- f- t-- 
05 05 05 05 05 05 



Cp © © O O to 
05 w CO to 50 to 
»15(ONSiCiO 
O O 05 05 © © 


'■’"OOOCOO 
MCJO^COO 
•xmCINCC 
O O 05 © © 05 


© O o C) CC CO 
rr rr 05 05 CO 
t 1 : o CD o - - 

—ggsggg 

OOOOOO OOOOOO------ 

•O to to to to »0 to to to tOtO to tOtOtOtOtOtOtOtOtOtOtO‘OtOtOtO to to to to to to to »0 to to to to to to to to to to 


©MHH00 0Cr-4CO©00 00t'-W500MC© 
-c x i-~ r- xcxco'Ot'ho.') to 
oc iooooccaoc (C<oo6ocoooo 
2 : 2 > 2 'S 0 <= ' 0 ®' 2 ? 2 > 2 ? 2 :<->^ 2 ? 

_50 0 0 00 

to to to to to to to to 


co -t« to 00 r>» 00 
a oc r- <n o a 
to to OC' OC to 

-> r^-1— r^- 


N ® N N © Tf 
HH^-tONN 

to to *- M Cl (N 
r^-r- c- — 

3888bo 

o *0 to to to to 


rr M 00 00 00 to 
«-• cr. (o hh 05 
co t o 00 00 to '-r 
~ ©»i - r>. r>. 


N CO 05 N v5 »-• 
*■ 5 CO rr tO -T 



05 to co t-H 05 rr 
—4 CO *0 rr CO —4 

SSSSp® 

ooo8< 

to tO »o to t 


CO to m 00 00 
m co oo © © oo 

»0 *o CO cO rr 

-> 00 00 00 00 


- ,JNNf-iNO500CCi0C0(MOCI(0 
qpqocpcp55XXgcpcpcCqp25®qo 


tPOHHlON 

GO 05 CO -r 05 GO 

totooor ■n-tr 
O'. O c» N N 

888888 

to tO to to tO tO 


co I s * o 05 o *r 
O —« to to I - GO 
•O tO H rH Cl Cl 
t- r-- I — 05 o 

888888 

to to to to to to 


to hh M f- co CO 

S © co m © 
to OC CO to rr 
05 05 r- 

888888 
to to to to to to 


00 CO to rr 00 C5 
Cl O N 05 -T to 

co co to *o M 65 

05 05 t'- r- 

888888 

to *0 to to tO to 


NKCOhC^ 

— C5 CN ^ to rr- 

— -- - u x 



05 to to 05 CO to 

SPSKgg 

228£gr 


© rr CO hh 00 © 
CO -r CO 05 00 rr 

to to CO (O 
* 2? 00 00 c© oc 

3S88 

) to to to 


(CHoaootj.ooo5» _ _ 

(OWt-NHXHOlMOKH. 

accccccogoogoccocooooo^ 


00 00 © rr © CO r-4 to to to •— CO 

8 r^ 05 co »-i co to oc (p 

to OC to to to *0 1—4 »*h M O'! 
-. r^- r— t'- r— ^-r-r^-r-c- 

? 8 S 8 f 


_J8888S 

to to to to to to to to to to to to 


rr 00 co CO 00 05 
Cl CO C O (C 'T 

co co to <o M m 
-5 

>8888 
5 to to to to 



05 C5 05 05 05 05 

»-H —H >-H 1 —< T—( t-4 

05 05 0 : 05 05 05 

_< r-< 1-4 

f—' •—< 1—4 T-4 f—1 —< t—4 *-4 r—* 1—4 »—4 ^4 »-4 

M M M M M M 

©©©©©© 

HHHHHH 

CO 00 00 00 00 00 

1 1 1 1 1 1 

1 1 1 I 1 1 

TTTTTT 

777777 

*—< r—! 1—4 •—4 1—4 *—4 1—4 1—4 »—< »—4 »—4 »—4 1—1 rH 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

^-4 »—4 »—t r4 r—i 

1 1 1 1 1 1 

HHHHHH 

I 1 1 1 1 1 

M M M M M M 

1 1 1 1 1 1 

1 1 1 1 1 1 

C»««C1C1C1 

1 1 1 1 1 1 

CIMNCICICI 

to *0 *o to to tO 

4- + + + + + 

CO CO CO CO CO CO 

1 - 

1 1 1 1 1 1 

<M<M<M<MM<N 

OOOOOO 

H H H »—i 1—4 

1 1 1 1 1 1 

cococococococococococococococo 

0505 05 05 05 05 05 05 05 05 05 05 05 0: 05 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

O O C © O © 

777777 

00 00 00 00 00 GO 
© © © © © © 

1 1 1 1 1 I 

©©©©©© 

© © © cO © © 

1 1 1 1 1 1 

© © © © © © 
M M M M M M 

777777 

•S"(f rT"T 

1 1 II 1 1 

05 05 C5 05 05 C5 

1 1 1 1 1 i 

++++++ 

CO CO 00 CO CO CO 
<N<MMM<M<M 

1 II 1 II 

CO CO CO CO CO CO CO co CO CO CO CO co CO cO 

+77+7+++++++7++ 

© © © © © © 

HHHHHH 

1 1 1 1 1 1 

M M M M M M 
++++++ 

© © © © © © 

CO CO CO CO CO CO 

1 1 1 1 1 1 

t". 1 ^. r>- 

MMMMMM 

eo co to co -r 

(OCO WdiH 
++++++ 

r-4 i-4 O 1-4 M M 

+ 4- 4*4-4- 

to to 1-4 M rr M 
++11++ 

trNHC^COMVOOCOWMMM 

+ *f+ +4- + + + + + + + 

©XNWVH 

+ 4-4- 1 + + 

rr rr H H fH m 
+++111 

© © r— © © co 

1 + + + + 

l>» © © rr © CO 
++++++ 

O 1-t CO 05 CO 

S 8 8 

1 1 1 1 1 1 

co t^- r- 05 -*r cm 

CG tO C Cl C Cl 

1 1 7777 

-246 

-233 

1-284 

-149 
+ 13 
!+ 55 

to O 05 CO H 
*- CO rr M 00 C5 

M r-H *—< 1 —< 

II 1 1 1 1 

<DN4)<XNhhM<COM- 4XOO 
XtrN^I-OMXh-NOOaMfrM 
rr rr rr rr rr rr CO M H H hhm 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

tflXHHNS 

CC i-4 M © 00 H 

H HH *—4 

1 1 1 1 1 1 

00 © © © rr © 

© CO M © 

1 + 1 1 1 1 

© 1—4 rr CO © 1—4 

§ £h m m m m 

1 1 1 1 1 1 

M © hh © © © 
XOM rr Jr 0 

r—4 *—< i-H •—4 ^H 

1 1 1 1 1 1 

05 00 05 05 05 0 

1 I 1 1 M 

05 C5 *-• 05 00 CO 

1 1 7 1 17 

00 00 00 05 05 

1 1 1 1 1 7 

00 00 00 00 

1 1 1 7 1 7 

05 05 05 05©i005ccr^00c00c©0 

1 1 1 1 7 1 1 1 1 77 1 1 77 

r-4 © © © 1 —< © 

1—4 

1 II 1 1 1 

00 © © © © © 

1 1 1 1 1 1 

©©©©©© 
77 1 1 1 1 

© 00 © © 00 © 

1 1 1 1 1 1 

. 5010S19 
. 5010860 
.5010010 
. 5010024 
.5009845 
.5009841 

.5010626 
.5010621 
.5009806 
.5009831 
. 5009639 
. 5009662 

4*NOC*flH 

CO to rr 05 M *p 
tt ~r CO rr •—• O 
0005 0500 

Q O O O S O 
tQ to to to »o »o 

.5009S56 
.5009818 
.5008947 
.5008946 
. 5008697 
.5008700 

.5010464 
.5010461 
.5010258 
.5010267 
.5011474 
.5011385 
.5011337 
.5011226 
.5009925 
.5009890 
.5010029 
.5010018 
.5011152 
.5011206 
.5010203 

.5009864 

.5009822 

.5008072 

.5008060 

.5007697 

.5007721 

.5007599 

.5007600 

.5007292 

.5007289 

.5009388 

.5009444 

. 5009901 

. 5009858 

.5008169 

. 5008194 

. 5007820 

.5007841 

.5009556 

. 5009602 

. 5007854 

.5007889 

.5007565 

.5007604 

.5010890 
.5010906 
. 5010034 
. 5010070 
.5009877 
.5009864 

.5010718 
.5010678 
. 5009862 
.5009915 
.5009680 
.5009695 

.5010410 
. 5010363 
.5009555 
.5009414 
. 5009038 
. 5008948 

. 5009823 
.5009746 
.5008851 
.5008866 
.5008608 
.5008582 

.5010349 
.5010350 
.5010147 
.5010161 
.5011366 
.5011282 
.5011242 
.5011119 
.5009817 
.5009786 
.5009924 
.5009899 
.5011048 
.5011094 
.5010083 

.5009806 

.5009728 

.5007958 

.5007951 

.6007639 

.5007670 

.5007538 
.5007509 
.5007188 
.5007196 
. 5009310 
.5009334 

. 5009894 

.5009835 

. 5008156 

. 5008171 

. 5007781 

. 5007821 

. 5009399 

.5009431 

.5007692 

.5007748 

.5007432 

. 5007441 

hhOOQO 

CD CO tO CO O CO 

co 00 0 O C* CO 

tO tO CO CO CO CO 

CO CO to CO 1-4 *—« 

CO CO CO CO CO CO 

C5 05 to co O M 
tc to CO CO co co 

OOOOtOCOfMMM©-rtO-H*—« hMM 
tOtOCOCOCOCOCOCOCOCOCOCOCOCOCO 

tCiGMNOM 
IQ tQ CO CO CO CO 

© © CO rr rr © 

© to © © © © 

CO © © 00 © 1-4 
© © © © © 

© f>. © r-4 © 1-4 

to © © © © © 

20.50 

20.74 
21.10 
21.22 
21.42 

21.75 

l>» CO to 00 1 -t 
C5 CO to O TT C5 

cd cd 00 

OC CO GO CO GC 05 
oc »o r- »o co (O 

0 O r-i 06 cd 

WClClHfHH 

20.18 
18.93 
18.34 
18.09 
16.98 
17.18 

i-4NNMtrXC; OQi-«t^OJCOO:cCOO 
COMCOrrcOtOGOtOMOOOii-HMOrr 

cdcdcdcdidrrMOor^or^oooi© 

MMMMMMMMi—<«—*i-4i— 41 -H 1 —4M 

CO M © rr © O 
© GO GC' M © GO 

oct^t^r^cdr^ 

r—4 *-H r—» r-4 

XOONN(D 
r-4 00 M 00 © © 

©+©©©© 

19.88 
19.09 
20.35 
20.56 
19.99 
21.24 

© 00 M © tO © 
© CO hh to © © 

© GC 00 © © 

*>. r>- 00 00 t>- 0 

r-t 1 —» r-H M i-4 Cl 

00 co f-t CO O 

hhNhhCI 

tocotor^ooo? 

p4 H H H H N 

CO to CO 00 CO 05 

HHHHHH 

trtrlrCOONXNNXOJMCCOH 

nHHHCiOHHHHHHHHN 

0 © © 

1-4 1-4 1—4 »—« M r—4 

co 00 00 00 

XNXXNtr 

© © 00 00 rr 00 

C^HHHHH 

»-• O O r-t 

-*r td »o td td 

00 CO 4T H f-4 CJ 

rr td td td »d td 

H H GO O O CO 

td id ^ td td td 

NNHMIOC5 
rr rr td td rr rr 

a5i-4C5i-4©ocT5io©coocorro5ai 

'Ttdrrtdtdrrrrrrtdtd^rridrrrr 

'T H © M CO © 

td »d rr id id + 

HH © 00 © *-4 00 

© © rr © © rr 

M rr 00 00 00 00 

© © rr rr rr rr 

I s - © © © © lr» 
rr rr td TT rr rr 

231.58 
230.70 
250.24 
249.90 
254.43 
254.54 

00 00 co *-H »o co 

C* QO 4r 00 X Cl 

to to to *r 05 05 
CO CO to to to ‘O 
c4 CM (N (M (N CS 

COV N it X h 
'W' CO 00 05 rr rr 

05 05 05 CO ■'T CO 
MCCOCONN 
<M <M (M <M Cl (M 

rr rr M rr to 00 

1-H 1-4 05 05 C5 00 

rr to 05 05 I s - 

to to lr N X X 
M M M M M M 

MI'-©r-40C00Mi-l©GCt^rr|r.OCC 

rrrr<M©CO©OMrrMt>-©COcOiO 

cdcn>rrrro6o-4cd(Ncdc'. OrTCCtd 
CC CO rr rr 1-4 M M M tc ‘O rr to M M rr 
MMMMMMMMMMMMMMM 

OMMIrcOX 
© © M © CO M 

cd td © © td + 

tO tO 1-4 1-4 M M 
M M CO CO COCO 

© © rr 00 © M 
© rr CO rr 00 M 

© © cd cd cd td 

M M rr rr O © 
CO CO CO CO M M 

M © CO © HH to 
© © © © M CO 

cd rr cd © © © 

© © © O N H 

M M CO CO CO CO 

262.12 
260.88 
318.81 
317.39 
330.98 
329.26 

00 TJ* -*• co 01 to 
0 N O N 0 01 

0 05 05 06 co co 
CO -T ■n to *0 
C 1 NNNCKN 

233.76 
234.62 
254.00 
252.65 

258.77 
258.38 

W^NOO 
co *-4 0 05 

0 i-H (M cd ai 

»r 4f 0(0 NN 
WNNNNN 

255.00 
257.02 
282.97 
282.48 
290.92 
291.81 

OGrrOCCOr^OOrrOOOCMtOGOtOrr 

OCXiT.ir^xrt-O'tOf'X'f 

MMcdcDONMididtONcdcdidod 

rrrrrrrTMMMtOtniOtOtOMMrr 

MMMOIMMMMMMMMMMM 

tO © © M 00 © 
rr rr © ©l- to 

td rr rr cd 
IO © 1-4 r- M M 
M M CO CO CO CO 

332.14 
333.44 
348.28 
347.94 
269.04 
268.34 

00 © CO © 00 © 

rt N O rr N H 

cd + cd *-4 © 

© © © © M M 
M M CO CO CO CO 

00 00 © © CO 00 
rr © © *-H 00 rr 

cd »d »d co © © 
© © M M CO CO 
M M CO CO CO CO 

Feb. 13-14... 

Feb. 14. 

Feb. 14. 

Feb. 14-15... 

Feb. 15. 

Feb.15. 

Feb. 26-27... 

Feb. 27. 

Feb. 27. 

Feb. 27-28... 

Feb. 28. 

Feb. 28. 

Mar. 13-14... 

Mar. 14. 

Mar. 14. 

Mar. 14-15... 

Mar. 15. 

Mar. 15. 

Mar. 24-25... 

Mar. 25. 

Mar. 25. 

Mar. 25-26... 

Mar. 26. 

Mar. 26. 

1 1 ■ « 1 1 1 1 iO • *H • • 

*T : :°? : : JTdoiJ-J 

<itrI^NXXXC:OjdiHiHr4i-4H 

&Q,P,P-ftP,P,p4p4P4p4p4P4p4P4 

Apr. 21-22... 

Apr. 22. 

Apr. 22. 

Apr. 22-23... 

Apr. 23. 

Apr. 23. 

May 3-4 . 

May 4. 

May 4. 

Mav 4-5. 

May 5. 

May 5. 

May 12-13... 

May 13. 

May 13. 

May 13-14... 

May 14. 

May 14. 

May 24-25... 

May 25. 

May 25. 

May 25-26... 

May 26. 

May 26. 

qoooflfi 

qcoflqq 


caofififi 

POQOPQOPQQfifiOOO 

PPPPPP 

PPPPPP 

PPPPPP 

PPPPPP 

•*r **r to to co co 

nnnnnn 

-Tf tO to co co 
«««««« 

rr rr to to CO CO 

PQpqffiWcqa 

rr rr to to co CO 
WPQCQttPQpQ 

tOtOCOCrrrrrrrrrcOCOtOtO , r»*rrtO 

amapaamawappBWW 

rr rr © © © © 

© © © © rr rr 

■<<!■< <5 •< 4 ) 

rr rr © © © © 
<<<<<< 

rr rr © © © © 

r-« O* OO -4T tOCO 

r-1 Cl CO *^4 10 CO 

H M CO rr toco 

1-4 M CO rr »0 CO 

HNWVtOCOtrXOOHNeO'ftO 
rH rH ^4 »-r r-4 

HH MC0 ^* ©© 

HNCO^IOO 

HH M CO rr © © 

H M CO rr © © 


Si 

jit 

N 8s 


dWss 

z 



«« 3 

©fc<W 

z 


« M 
8 

2S 

li 

c3 72 
Q<j> 


2 P 

o’fen 

z, 


3 ^ 

M tc 

il 

tfii 

S3 

r-H 05 





©e« 

z 



-w 

tr> _ 

A E 
•C.2 

•S s 
a.2 

* . 

35 

oi£ 

- ^ *H 

0 

hh oj 


S 3 

-S3 

oOM 

oHCC 

z 

Z 


MM 

O HH 

Is 

rj 
• tuO 

^3 

od2 

•ecq 

. 

p • 

3 W 

C3 

O H 

h 

r & 

PQ § 


ooS 

dcoB 


Z 

z 


59387°—17-10 


















































































Pendulum observations and reductions —Continued. 


146 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


a 

c3 

o 

a 


8 


CM © 

ec8 

© CM 
© O 
© O 

Is 

050 

©d 

d© 

fe-H 

S-H 

CO _ii 

© Tl 


SI 


I o 

i-H 


8 


tp O -h I'- © CO 
CM'CCOO 
CO CO CO OO tp tp 

© © © © 05 © 
t>- c- t>. t'- r- t'- 
C5 05 05 05 05 05 


© C O 00 © Q CM 
Ct ^ ic if 1 O 

40 © © © »o © 

05 05 05 05 05 05 
05 05 05 05 05 05 


cm co tp © tp 
(>•0(0 1000 
r- 

o o c? o d o 

CO CC 00 OO X 00 

05 05 05 05 05 05 


CO tP CC © 

05 3 05 CO 05 
© © © © © 


o 

CO 

05 


■s 

i 

o 

o 

■s 


§ 

© 

a 


fr.CM©l>.©^Hr>.©CO©GOCMOO 

40NNO(OOOOM*QP)iO*Q 

COCOMCOCCOOOOCUNiNCl 

•OOOCOOOCOOOCOOOOOOO 

°S8g8S8888o8S3 

©©©©©©©©©©©©© 


ChCMOOCCCO 
C0»0O05CM'^rCMr0'^r 
CM CM CM CM O O O O 
CO % CO N N N I - N N 

888888888 
40*0404040 40 O »0»0 


005NN40 00 
(CtOJOj T 
CM CM -r 40 O O 

coooxccoo 

Sc8888 

40 40 40 40 40 40 


O 05 rr 0 * 40 Tp 
NOOCJ^th 
NNtOtDOO 
05 05 1^ 00 OO 

888888 

40 40 40 *0 40 *o 


St 


(00X^0 
)©©*—<©© 
—» CO O 05 40 40 

888888 

40 40 40 40 40 *0 


CD O-H CNCO 

oc o co os cD 

o © CO CO © © 
r- r>. © © -p tp 

8 88888 

40 40 40 40 40 40 


S 

8.S2 


<D©©©cD©CM©»-«©©©© 

’rO00CC'X'C3O-'^"r't~O 

S COCOCOCO©CD«D<DCMCMCMCM 
COOOOOOOCOOOOOCDOO 

“8888888888888 

4040»0*0404040*0404040*040 


NOM*rOlNCO-HN 
CM*rOaCM»OCO»0^ 
CM CM CM —« CM O © © O 

co oo oo t>* r>- £>• t>- r>» 

888888888 

4040*040404040»0*0 


00 CM C— © CM © 
CO CD 05 O TP CO 
CM CM -r 40 C © 
0000X00 00 

S 08888 

40 40 40 40 40 10 


C5 CO 05 00 CM 05 
CO N *C N H 
NNCOOCO 
© © l- OC 00 

888888 

40 40 40 40 40 *0 


050CNXH 

r-< *0 O CM *0 CO 

co 0 O; © »o *o 
co co Tt* Tp tp tp 
© © O O O © 
OOOOOO 
40 *0 40 40 40 40 


05 CO CC 40 t'» 
O CM Cl 05 
ococcoo 
h. u; 10 Tj* -T 

88888 

40 40 40 40 40 


S d„ 

07" 

2 fe® 

5° 


_ J040t00-<05WNCO«---. 
CO CO TO CO CO CO CO 40 CO CM CM CM CM 
•OOOOQOOOOOCOCOCOOOCOCO«~ 

“ 888888888888 ! 

40»0*0404040»04040404040' 


40 CM t^- CM CM »—< CD "D rr t^NiOX-H 

*t CO 05 o CO •n' C CM CO cO CO C5 O 2 ; © 
CMCM-hCMCMOOOO CM CM -r © © © 
OG 00 00 t'- (^ r^. t-~ O O OC 00 00 00 

888888888 OOO 080 

40*0 40 40 40 40 40 40 40 40 40*0 40 40*0 


Tp CM 00 —< 00 © 
CD CD SO *-T — © 
NNCONOO 
C5 © oo oo 

888888 

40 40 *0 40 40 40 


JCCOC_ 

TP 40' © *— © 40 

cc cd C5 c; *o *o 

CD CD TP TP TT tp 


05 05 05 CO c. - 

O O CM CO 05 05 

t>. h. ifl 4T, r T 

8 88888 

*Q LC tO lO iO kC 


© 

© 

Flex¬ 

ure 

7777777777777 

-11 

-11 

-ll 

-ll 

-ll 

-ll 

-ll 

-ll 

-11 

t>- 

777777 

CM CM CM CM CM CM 
CM CM CM CM CM CM 

1 1 1 1 1 1 

tP tP Tp rp Tp tP 

777777 

© 

7 

© © © © © 

»"H *—< *—• *—< 

1 1 1 II 

P< 

a 

© 

Chro¬ 

nom¬ 

eter 

No. 

1841 

©© ©©©©©©©©© 40© 
©©©©©©©©©©©©© 

HHHHHrtHHHHHHH 

1 1 1 1 II 1 1 1 1 1 1 1 

CMCMCMCMCMCMCMCMCM 

©©©©©©©©© 

777777777 

00 00 CO GO oo 00 

777777 

© © © © © © 
CM DJ CM CM CM CM 
CM CM CM CM CM CM 

1 1 1 1 l 1 

OOOOOO 
CO CO CO CO CO CO 

777777 

00 

© 

1 

00 OC 00 C< CO 

© © © © © 

1 1 1 1 1 

'O 

5 

Ph 

Chro¬ 

nom¬ 

eter 

No. 

1823 

OOOOGOCOOOOOGOOOOGGOOOOOCC 

+n 

+n 

+n 

+n 

+n 

+n 

+n 

+n 

+ii 

CO CO CO CO CO CO 
©©©©©© 

TP TP Tp TP Tp 

1 1 1 1 1 1 

©©©©©© 
Tp TP TP Tp Tp TP 

++++++ 

+ 52 

CM CM CM CM CM 
© © © © © 

§ 

CO © 

COCMw©tt©tj*tJ'CM©CMOOO 

©©©■xfTrTfCOCMCM 

Tt* Tp CO CM © TJ» 

© GO © Tp CO *-H 

00 Cr © © © 

© 

© © TP CO 


■ H 
jp 3 
3. M 


+ 


++++++ 


++++++ + + + + + + 


i 


o 

O 


g££ 

© a> G 


ICMi-Hr—-CMCMCMCMCMCMCMCM 

I I I I I I I I I II I I 


COO*Or-CDCMCOCMCO TT 40 05 40 00 ^C5 05 050N 
CO CO CO CM CM CO CO CO CO HCOhttXC’5 i-h © © © p © 
CM CM CM CM CM CM CM CM CM —• CM CM r-n -h CM CM 

I I I I I II I I +++ + + + I I I I I l 


I + + 


I I I II 


w 

L 

< 


0000005000C500 05 000C50 

IMMIIIMin 


00 OS 00 OS OB OS OS OB OS (O C~ 00 00 OB 0050005000 ocoosoco 

iiiiIiiii i i i i i i 7 i I m i iii 777 


00 03 OC' O O 


•s 


o 

o 


S o' 

£fe« 


©*—r^COt'-©r-OCCC©©CM© 
40NCC40*rOiOOfCT'T'CtiO 
StstsSSCOCOCOOtOC 
•XXXXXCNNNOODO 

"8888888888888 

©©©©©©© ©©* 0 ©* 0 © 


<Dt^Tt*OTpCM40C0»O 
CMXOXMO WOtt 
CD CD CD 40 CD TT* TT TT Tp 

oo oc co t'- r- i - t- 

888888888 

4040*040*040404040 


tp CM *0 CO 00 O 
40 CO 00 CD *0 © 
»r T' CD CD O O 
© G 00 CO 00 00 

SS8888 

40 40 40 40 *0 *0 


OU-tHWOt 
40 CM »-m CO © 00 

Cm C) -i -< iC rr 

© © SO CO CO 00 

© © © © © 3 

40 40 *0 40 40 40 


40©CCCC'5-N 
CO OC *0 © © O 
r-t'-ooi-t- 
o d ‘O is -tf 
©©©©©© 
© © o © © © 

40 *0 40 40 40 40 


© © CD Tp tt CM 

CO 00 © CM CO © 
CM CM *0 *0 h «-> 
I'- (>. © *o *o «o 

8 88888 

40 40 40 40 40 *0 


G 

p 

1 

fe 

Ph 

Chronom¬ 

eter No. 
1823 

s. 

0.5008615 
.5008631 
.5008586 
.5008564 
. 5008584 
.5006848 
.5006855 
.5006828 
.5006854 
.5006517 
.5006472 
.5006494 
.5006481 

.5008481 
.5008496 
.5008435 
.5007434 
.5007463 
.5007278 
.5007245 
.5007265 
. 5007277 

.5010216 
.5010173 
.5008451 
.5008125 
.5007830 
. 5007792 

.5010002 

| .5009988 

. 5007895 

.5007941 

.5008281 

. 5008249 

.5006611 

. 5006609 

. 5004877 

. 5004905 

. 5004517 

.5004519 

.5007165 

.5007143 

.5006346 

.5005382 

.5005038 

.5001985 

Pres¬ 

sure 

JhNX©OXOOCM©NtN 

{£©©©©©©©©©©©©© 

E 

©©©OOOthCMCM 
© © © © <D © © © © 

© © o *-• rr. oo 

© © CD © © © 

*o © © *-r CO 
© © © SD <D SO 

© © CC © f'- CC 
©©©©©© 

OO 

© 

58 

63 

57 

60 

61 


a££ 

. CO © *-* »"■* © 00 © 00 © 00 © »—* CO 
^©©DtrOTTfrCOTMCM 

© GO O »—< O CO © CO © 
©TT©tPtji©©©© 

© © © — a> »-* 

CD CM CD OC © CO 

CO © © © 00 CO 
O i- © 

CM CM 3 © © Tp 
O 1-t CM tp o> © 

© 

© 

© CC 00 CO 00 
O OC © © tr 


© © 3 

0 od©©©dddpopdd 

° CMCM»—(CMCMCMCMCICMCMCM 


TP TP TJ- CO O © 

r~i *—( *—i *—4 r—( 

c © © © © © 

CMHHHHH 

4r! © © Tp Tp 


t''* © © © © 

!—• r—i r—i r—* 


O 

*- 

05 

■+-> 

o 

E-* 


as 

a 

s 


pj © © © oo 40 © co © oo © © oo oo ©ocr^t^oor^ooo© r-t cm © co »o oo 

g tH «“H i-H CO »-H »-* rH r4 i-H HHHHHrtHHH M i-J iH rt i-i i-i 


© *0 © 40 © © CC CO GO CO CO CM*040t^l'- 


jJ©©©©©©©©»—<©CO©CM 
c? 40^'V'PVT'^P'T4040T’'»r40 


CMO©©»-4i-tOO©»-i 
40 40 ^ 40 *0 40 »0 


r^t^oor^i^t^ © © r-< 

WTJ* *0 40 TT 40 40 © 


CM 00 »-h CM CM CM 

*o ^ *o *o *o *o 


f-M CM CM r-. CO CM 
© © © © © © 


© 

o —. 
C eJ 
© > 
T3 *- 
*o -2 

.s 

o 

o 


6 A °’- 
£ az* 

s36s.» 

O 


8 


«©©©©©©t>.i^r^©©©©© 

co co co co co *o *o »o »o 

CMCMCMCMCMCOCOCO CO CO CO CO CO 


© © 00 © © CO 

co ”T co co —• —< 

CM CM CM CM CO CO 


TT TT CO I'—r ‘O 
tt © © © © 
CM CM CO CO CM CM 


© CO © *—I CM T-* 

r^. © © © co co 

CO 00 ^4 r}4 © © 


CO CO ^ CO CM —' 
Tt* T(< © © CO OO 
CO CO -M* rf ^ "*3* 


iiOM 

ll5S 

o a £*“ 


•©■^'t'-40CM©CM* 


CM CM CM CM CM CO CO CO CO CO CO CO CO 




©'<T©©©'*J'©TTP 

OiC5C2COCOtttt 

CMCMCMCOCOCOCOCOCO 


© © © I''- © y-4 
T TP 05 © CM 

CM CM CM CM CO CO 


© © © CM CO 

4C *C -H r-t © © 
CM CM CO CO CO CO 


CO GO CO © O* CO 
r» h h © © 
co co © © © © 


© 

TP 

CO 


© or ©©.— 

© CD © © © 

co ^ © 


© 

u 

8 


© 

GO © 


• © © © ! 

^©^^-^♦-•^^©©GOOO 

•■H a)DC5DOOOQJC;CJOCJCJ 

3 :13s:3s!3333dd3 


© 

•-H 

*i < 


©oo©cir^t^r<-oc 


a)QJC/'Q5<L‘<15<D<D<D 

cflflaccccg 

hhohhhhho 


C^ co CO CO TP TP 
>>>■>> >»>*>» 
z3 S3 3 33 


I »-m 

So ^ ^4 
3 333 3 3 

i-s *-s i-> •-> 


CM 

CM 

I 


8 


to 

3 

I 


’CM * 
-> r^C"l 


r^ . t», So So So So 

ssa 1 ? 3 "3 


>5 . bfitfitSCM 
•=-<333 = 


g§ 

e- *> 


fiQQflflflflflflfifififl QOOQQQQQQ flOOQfiQ PftQQQa flfififiOfl Q fiQQCO 


a;fl 

as 3 w 

3.-0 3 


■^-r^rTPTP©©©©©©©© rpTp-r©©©©©© tt tt © © © © rp -^« © © © © -rp ^ © © © © tp © © © © 

<1 •< ■< <i <1 <! ■< <5 < <1 < <J <) CQ cq os W 05 ffl ffl pa ffl <•<•<<•<■< <; 


(BO 

•So 

^2 

oo 


*-< CM r-« DJ CO CO Tji © © © © c>. 00 *-M CM © CO-'f 4D © t>. 00 *-H CM CO ■*T © © rP CM CO tt © © rH CM CO ^ © © «-H CM CO © © 


CD 

> 


X5 

O 

•o 

3 

(9 

G 

O 

C3 

S 


roj, 

o: £S 

StAfl 

Ul 03 >STl 
c *-> 5- 

2 3 £; S 

3 O 3 C5 
«O0D33 


w 13 

£ O 3 os 
GC^Cfl33 


•g a 


ci 


3 

O S3 

d rfc 
2 om 

3 ^ 

S 3 

6E->ec 

2 JS 


gW 

- 13 E 

OtS 

3=3 

?o 

2cm 
§ 3 
oHPC 
Z 


3M 

3 

M a 

u __ 

°33 

s ® 

O M 
r s-c 
as 3 

oS® 

2 


2*3 

oP 

5 s 

la 

Vi 

©K* Ul 

55 


Aug. 2 












































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


08 

©d 

g-H 

© X 

r- g 
•c © 

Os *t1 

i 


Ss 

as n 

980.635 

±0.001 

980.770 

±0.003 

' 980.916 

±0.002 

980.374 

±0.001 

9X0.425 

980.425 

980.420 
980.412 
980.416 

980.421 

N 05 W CO 00 N 

cr. cd co »o t'- 
OiOiOiOiCO 

oococfd 
ix x x x /. x 

C5 95 O 05 95 05 

«HOX 

C* © © © 

oo ac oo 55 

OSCSCS© 

980.427 

980.438 

—'©osco^orxxco 
4D M* ID 1 C 4D to lO 'T O 

iO »Q *0 ‘O 40 40 40 *o «o 

cddddcccd 

CO X X cc x oc X '/ CA 

os a* as os as cs as as as 

CO CO CO 00 O CO 

eg co -t* eg co co 

(0(0(0 0 0 CD 

dodded 
r 0 r x x x x 
as o. a: a. cs as 

—• x »-4 © eg 
as t'- so co co co 

ddccgd 
xxxxxx 
cs as as as as Os 

980.920 ' 

980.906 

980.920 

930.902 

980.918 

980.914 

980.910 

980.920 

980.930 i 

980.372 ' 

950.372 

980.376 

980.373 

980.368 

980.380 , 

-t* »o o x r^- cm 

OC'fCMn 
lO O ^ V 

i - »o >o to ' O 

SSiSSS 

tO O O i-C 

.5007102 
.5007112 
.5005381 
.5005382 
.5006062 
.5005028 

.5007484 
. 5007488 
. 5005720 
. 5005752 

.5005398 

.5005369 

.5007182 

.5007187 

.5005392 

.5005400 

.5005072 

.5005057 

.5005064 

.5005419 

.5007170 

.5006985 

. 5006985 

. 5005204 

. 5005216 

. 5004882 

.5004876 1 

. 5006580 

. 5006614 

. 5004884 

. 5004S92 

. 5004551 

. 5004544 

. 5006253 

. 5006286 

.5004485 

.5004530 

.5004147 

.5004157 

.5004168 

.5004486 

. 5006226 

. 5007652 

. 5007652 

. 5005873 

. 5005882 

. 5005552 

. 5005522 

.6007500 
. 5007503 
.5005745 
. 5005768 
. 5005432 
.5005426 

.5007098 
.5007117 
. 5005383 
. 5005386 
. 5005062 
. 5005018 

. 5007489 
. 5007490 
.5005722 
.5005754 

. 5005396 
. 5005359 

. 5007189 
.5007195 
. 5005399 

. 5005403 

. 5005070 

. 5005048 

. 5u05045 

. 5005419 

. 5007176 

CCHOSCTlX 
NNChCCC 
CS O- CM CM X X 

CO 40 40 40 tj* rf 

SooSSS 

40 40 40 'O 40 40 

. 5006560 

. 5006603 

. 5004888 

. 5004895 

. 5004550 

. 5004562 

.5006247 

. 5006300 

. 5004487 

. 5004527 

. 5004133 

.5004163 

. 5004176 

. 5004478 

. 5006225 

. 5007652 

. 5007657 

.5005870 

. 5005878 

.5005555 

.5005520 

.5007507 
.5007507 
.5005746 
.5005767 
.5005422 
.5005398 

.5007106 
. 5007106 
.5005379 
.5005379 
.5005063 
.5005039 

. 5007479 
.5007487 
. 5005719 
. 5005749 

.5005399 

.5005379 

.5007174 
.5007179 
.5005385 
.5005396 
.5005074 
. 5005066 
.5005082 
.5005419 
. 5007163 

. 5007002 

. 5006996 

. 5005206 

. 5005214 

. 5004877 

. 5004855 

. 5006600 

. 5006626 

.5004880 

. 5004S88 

. 5004552 

. 5004527 

. 5006259 

. 5006272 

.5004483 

. 5004534 

. 5004161 

.5004151 

.5004161 

. 5004493 

. 5006226 

. 5007652 

. 5007647 

.5005876 

. 6005S86 

. 5005548 

.5005525 

77T777 

*r ^ ■*»* •** ■*»* -*t« 

777777 

(OCCCO 

7777 

to CO 

77 

1! II II II 1 

as as cs cs as as 

i i i i i i 

as cs as as as cs 

i i i i i i 

as as as as as as 9 as as 

HHHHHrlHHH 

1 1 1 1 1 1 II 1 

r- r- 

*-H r—4 i-H r-H r—4 r—4 

1 1 1 1 1 1 

c o -j: x> 

777777 

iO iO uo iO iO o 
40 113 0010 »0 

•—4 • r—i r—i r—> r—i 

1 1 1 1 1 1 

r—4 r-H i—4 r—4 

CO CO CO CO 

7777 

CO CO 

77 

cgxxxxxxxx 

*—4 r—1 •—* r—4 i—4 •—1 r—4 r—4 r-^ 

1 1 1 1 1 1 1 1 1 

as as as as as as 

XXXXXX 

777777 

xxxxxx 

r>- r- 

r—4 r—i r—4 r-4 r—4 r—4 

Mini 

xxegxxxegxx 

*OiOU5*CiD4DU5<OiC 

44 r— 

1 1 1 1 1 II II 

tO (D CD CD CD CO 

r—4 r—4 »—4 r—4 »—4 r-4 

II 1 1 1 1 

-*t* f -r 

CM CM CM CM CM CM 

+ + + + + + 

0(0(0900 

++++++ 

coop 

VrJ-rrT}' 

+ 4-4-4- 

+ 40 
+ 40 

xxxxxxxxx 

CM (M ON CM CM CM CM CM CM 

777777777 

x co x oo x cr 
o o o o o o 

777777 

as as cs os as as 

r—4 r—4 r—4 r—4 r—4 r—4 
r—4 r—4 r—4 r—4 r—4 r—4 

++++++ 

4*^1 —4 r—4 

+++++++++ 

oooooo 

r—4 r—4 r—4 r—4 r—4 r—4 
++++++ 


40 X -4 CM lO 


CO o 

r^coxi-ncoio^coia 

CM CO ^ CM 

X X co 40 rj* CO 


CM CM CD U3PJ 

++++++ 

++++++ 

++++ 

_L 

I 1 1 * 1 1 1 1 1 



1 1 1 1 1 1 1 1 1 



r r ! i t t i r 





N«0>0 0)0> 
X CM CO -t* iO CD 

Mill! 

—« OS © 9 

lO t ^ TT C4 (N 

777777 

40 ■*** CM ^ 
CO CO 40 o 

1 1 1 1 

© CM 

rS 

i 1 

cscCi— os to cs o x 

COC33CC-h«N 

71*7 177777 

(O -H T** CO 

lO 40 (D 40 LC (D 

1 1 1 1 1 i 

eg o cm ox cs 

•t ^ 1.0 CD CD a 

1 1 1 1 1 1 

xcoioasxcMr^xx 

lOCCCMCMOCOCMXiO 

r—4 r—4 r—4 r—4 »—» r— r—4 

1 1 1 1 1 1 1 1 1 

CM iC CM l>- O O 
CO M* CD (O O us 

T7TT77 

N0i©0 005 

Mini 

r- co oo o oo 

i i i i m 

r>.(ox co 

1 1 II 

os r- 

1 I 

XXCSXXCSXXX 

1 1 1 M i 1 1 1 

x x x x as 

1 1 1 1 1 1 

t>- r'. x x 

1 I 1 II 1 

NNNCCM^COOOCS 

II 1 1 1 1 1 1 1 

xxt»t^xr«- 

1 1 1 1 1 1 

.5007708 
.5007704 
.5005957 
.5005996 
. 5005674 
.5005678 

.5007420 
.5007437 
.5005706 
. 5005703 
. 5005366 
. 5005318 

. 5007697 
. 5007668 
. 5005923 
. 5005959 

.5005565 
.5005515 

. 5007456 
.5007460 
.5005663 
. 5005666 
.5005334 
.5005318 
.5005316 
. 5005691 
. 5007459 

. 5007181 
. 5007184 
. 5005415 
. 5005431 
. 5005094 
.5005114 

.5006789 
. 5006S29 
.5005128 
. 5005144 
. 5004804 
. 5004823 

. 5006581 
.5006612 
.5004787 
. 5004833 
. 5004416 
.5004471 
. 5004480 
.5004740 
. 5006458 

. 5008004 

.5017992 

. 5C06217 

. 5006232 

. 5005902 

.5005858 

.5007527 
. 5007520 
. 5005770 
. 5005807 
. 5005476 
. 5005462 

.6007257 
. 5007255 
. 5005531 
. 5005525 
.5005196 
. 5005168 

. 5007516 
. 5007494 
. 5005749 
. 5005783 

.5005397 
. 5005364 

.5007175 
.5007178 
.5005383 
. 5005303 
. 5005072 
. 5005070 
.5005087 
.5005426 
.5007180 

. 5006966 
.5006959 
. 5005173 
. 5005179 
. 5004836 
. 5001826 

. 5006532 
. 5006555 
. 5004823 
. 5004840 
.5004509 
. 5004491 

. 5006309 
. 5006300 
. 5004499 
. 5004556 
. 5004160 
.5004175 
.5004181 
. 5004471 
. 5006175 

.5007727 
. 5007705 
. 5005946 
. 5095963 
. 5005618 

.5005586 

<OCO O— 0—4 
U)0<0<00(0 

OOiH.*C(NOO 
O 9 (C (O C <0 

CO ^ GO Ow 
o 40 40 40 

S3 

(ONfHcoNCsor'Cs 
us lO (O (O >C ID O 1C >D 

hMCCOOh 
<0 CO ?D CO CO CO 

io co r- x os -h 
40 4C 40 40 40 CO 

rt HQ-CHHcr> 
(C O O 'D O C O O lO 

CM CM X 0 03 ^ 
CD CD iD CD iO CD 

N*ONO^O 

ONOCOOOi 

OiOiOMCO 

(ONiOO 
40 CO O'! CO 

CS ^ 

CO o 

©CMOl'-OOCMCMX 
co o ^ x io co co r- os 

4TJ CO US (O (/ r-4 
CO CO CC CM 40 

WCDWMHO 

o as cm tj* to co 

x^ocoN^joa) 

NMOSOiOhOhM 

gs eg r>- 
X -*r x os cc io 

icioioddco 

0C GO 00 » GC 

o id cd cd 

r— r—4 »— r—4 

40 40 

r—4 

rdrdrdrdrdr-dt-rdrd 

CO CO CO CO CO CO 

CO »o co CO jO co 

x<xt-7xi'7xxt7cd 

r^ i—4 —4 HHHHHH 

00 X X X X OC 

r—4 r—4 r-4 r—4 r—4 r—4 

CM ^ CD tc 

O M V lO CD 03 

oocsco 

40 CM 

coco»acocor»4occco 

M'MM'CONN 

as X CM CM CM ^ 

WHCOONhONCO 

X X CM CM CM as 

r4 r—4 r—4 r—i r—4 r—4 

^4 r—4 r-4 r-4 ^4 r—4 

HHHH 

r-< ^-4 


HHrtHHH 

C O —t —< —> —■ 

HHHHHHHHH 


f-'NWN'irco 

HMXNOM 

<-• OS CM CM 

CM O 

--i^CMOCO'-'^O 

OHC.ONO 

hmoOONh 

HCJCSONC^MCO 

CS O O X X CM 

iC 1C *o 1C o »o 

ic id T}" lO lO ID 

40 + 40 40 

40 40 

id >c us o u: id id ‘d io 

id lO + 40 40 40 

4C 40 , 'f 40 »0 40 

irdic + iOidiCiriidid 

USOUS M* US US 


X O O iO h CM 
X OCMM'H X 

X iO CM X X iO 
(D (O 00 CO CO 

CD 

X 40 40 O 

—4 CM 

r- x 

CMOCOCMOcgcDCMTj* 

X CO as !'• CM CD l '. X CO 

r-4 40 CM O CM 
(DiOHOCWW 

(O CC N CC 00 

io a u* as co 

OSOOcDCMOlO^fCM 

XCDt v -t > *CDcD4O0SCD 

iJ'hXtJ’CNH 
X X iO CD —4 X 

^USON^C 
CM CM CM —4 -rr 

i' d cd co co c 

X X X X CD t^r 
COX V'f VT 

»d cd ci d 

CM CM CM CM 
COX^Tf 

cd cd 
tJ* ..o 
rr TJ4 

id *d r— < *— 4 as oo as >d 
xx-f-^coi^r^xx 
XX^ , V'^'^ , ^ ,, «rX 

od x’ cm o —* as 

rf 'D (D OS 7. 

X X *r t 

x' cd cd o cd 

CD CD OC X CM H 

x x io io 

o x cm hiaoiooN^ 

Xt>-CM—' C u: 4!S CM X 
XXOiOiOiOtOiOX 

CM CO CM — * + 

— — O O CM CM 
X CO 1* Tt* Tt* T)4 

rfCDy,T)"f O 

(DC3NOOH 

Cl N ^ C CO CO 
C H 40 c CD CM 

CM CM ^ CD 
r- r-4 CO 

ss 

^OCHtOON^D 

as x as r-. x co as cm r- 

CM CD X CD CM CD 
^ X 1-4 iO ^ 

O X CD ^ r-4 o 
CM X X O 0-4 

M4onNus*-eiuseirt 

NMrHCMiOXiODX 

-)♦ r)4 CD CD CD CD 
OCSDNVO 

cjl CM X ^ l-oo 

£2 x x x »a o 

rtM’f VTf4 -4J- 

id »d CM cd »~4 -r 
rr lO 40 XX 

COCO'C’C’CT!' 

X + 40 CM 

X X X X 
COX’f'C 

eg cd 

CD CD 

■4)4 TT 

XX + + cdcdr-4--cd 
■^•TrcDcDasasasco--r 
xx^^^^^^x 

as a- eg cd od 

iO 40 / X — ■ -H 

x X ^ io «o 

cd —« x id 

CO OC H — iD ‘O 
X X 40 40 40 40 

cor^oas — csodasid 
cs a *o -t o a as *c o 
XX40 0CD40 40*OT*4 

^dcoidop 

CM CM CM -4 ■»* if 
CC CO 1? 4J4 ^ 4 

2 * :« : : 
i • • i • • 

CM CM CM X X 

HHHHHH 

CM • *CM * * 

iocoHH 
^ CM CM CM CM CM 

ec • ,co • 

XXX 

»—4 r—4 

* *. cm ; ; x • ; 

as » • o • • 

r-4 • • CM • » 

xasas^oo 

^ —i ^ CM CM 

x • • gs • • 
CM • «CM • • 

tj- x* x* X as gs 

C l CM CM CM CM CM 

• *••••••• 

t>T • • X • • OS • • 

cit^r-r^xoooiasas 

21-22... 

22. 

22. 

22-23... 

23. 

23. 

ex tfi ti tL tdO bi 
33S333 

3S3S53 

3333® 

CDC. 
© © 
coc n 

Or Or O. C*r O. Or Or Or 

©©©©©©©©© 

uiwinmviinuimw 

O. Or O-O-C- Or 
©©©©©©' 

CQ 0Q CQ W QQ XU 

Cr P- C- Or Or Or 
©©©©©© 

CC co 0 Q CC 0U CQ 

ocoooooo© 

ocooooooo 

4J p r J d d 

© © © O © © 

cooooo 

Qosaoo 


fiQflfi 

QQ 

CQQQCiQGCQ 

CQGQGQ 

OQflCGQ 

COpQGQOOG 

QPGQQP 

TT* iO 40 CD CD 
<<<<<< 

rr* ■*}* »0 O CD CD 
««« 

to »o 

<<« 

CD CD 
« 

■4)4 Tt< lO lO CO co CO 40 
<<<<<<<<<4 

«f 4f iO iO © O 
<<<<<< 

4« if io iO (D CD 

<<S<J<J<J<I 

■^nr^iOCDcDcDiO^ 

<<■'’■<<<<;<<! 

S' US 40 (D (5 
««« 

HCMWM»USCO 

HCMXM*iOCO 

HNW'f 

40 CD 

HNeo^irscor-cooi 

rH CSX ■*« 40 CD 

—l CM X ^ iO CD 

-^CMx^iocot^xas 

1 -H CM X ’4J4 40 CD 


sn 

5z: 

h 

S 

03 

©3 

2 

O 


04 


£ 

oZC5 

6 

55 

Z 



r- © 

l£f 

«5 . 
C M 

© i-4 

fa 

d£ 


feM 

a © 
d Sb 
•d i— 

*7 W 
f-4 rH 

coy 

> 

si 

•r-4 

il 

*3 3 

x: i5 

Iron 

Will 

r. 

si 

S 3 

. 

l-r 

•^30 

4-> , 

* 

1-4 

0. 67. 
Mich., 
Burge 

s| 

0. 59. 
Dak., 
Burge 

S 

i« d 

'A 

55 

A 











































































Pendulum observations and reductions —Continued. 


148 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


Mean g 

Cl 












i 

ci ::::::::::::::::: : 






| 

Mean 

*. 

0.5008324 

.5008316 

. 5008321 

. 5006560 

. 5006561 

.5006562 

.5606200 

.5006210 

.5006190 

.5006196 

.5006200 

. 5006208 

. 5006214 

. 5006216 

. 5006210 

. 5006220 

. 5006229 

. 5006199 

. 5008357 

. 5008346 

.5006577 

.5006566 

. 5006222 

. 50U6242 

.6008369 

.5008354 

. 5006595 

. 5006595 

. 5006249 

. 5006246 

. 5008260 

. 5008254 

.5007220 

.5007220 

. 5007012 

.5007039 

. 5008362 

.5008361 

.5006600 

.5006584 

.5006238 

.5006229 

i 

o 

© 

■8 

a 

Ph 


Chronom¬ 
eter No. 

1841 

*. 

0. 5008325 

.500x317 

. 5008323 

. 5006551 

. 5006564 

.5006571 

. 5006194 

.5006208 

.5006194 

.5006200 

.5006194 

.5006209 

.5006215 

.5006213 

. 5006217 

. 5006226 

. 5006237 

. 5006196 

©00 050h-N 
lO rf I- lO -- © 
CO CO O © CM CM 
OO CC © CO CO CO 

S8S8is 

iO iO *C O iO O 

.5008369 

.5008343 

.5006608 

. 5006583 

. 5006249 

. 5006258 

.5008261 

.5008213 

.5007233 

.5007208 

.5007013 

.5007052 

.5008355 

.5008359 

. 5006608 

. 5006592 

. 5006231 

.5006233 


Chronom¬ 

eter No. 
1823 

s. 

0.5008324 

. 5008316 
. 5008319 

. 5006570 

. 5006558 

.5006553 

. 5006206 

.5006213 

.5006186 

.5006191 

.5006207 

.5006207 

.5006214 

.5006220 

. 5006203 

. 5006214 

. 5006221 

. 5006202 

.5008358 

. 5008345 

.5006575 

.5006582 

. 5006227 

.5006221 

. 5008368 

.5008365 

.5006582 

. 5006607 

. 5006249 

. 5006233 

. 5008259 

.5008261 

. 5007208 

. 5007233 

.5007012 

.5007026 

.5008368 

.5008368 

. 5006591 

. 5006576 

.5006215 

. 5006225 

i— 

© 


Flex¬ 

ure 

tO©OCCCDCD®tOCCCCCOtOC©OCDtOtO 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

NNINNNN 

1—4 rH 1—4 •—4 T—4 P4 

1 1 1 1 1 1 

CM CM CM CM 04 CM 

i—4 h 4 rH r—4 r—» rH 

1 1 1 1 1 1 

- 14 

- 14 

- 14 

- 14 

- 14 

- 14 

CM CM CM CM CM CM 

HHHHHH 

1 1 1 1 1 1 

o 

1 


© 

Chro¬ 

nom¬ 

eter 

No. 

1841 

cococoCMCMCMcoeocococococccococococo 

777777777777777777 

ft* Tf -*< TT Tf Tf4 

oaaocc 

i i 1777 

co co co CC CO CO 
t'* C'- I s - 00 CO 00 

1 1 II 1 1 

CO CO CO CO cc co 
r- r-cc cc oo 

1 1 1 1 1 1 

D O 03 C3 03 O 
lOUJlCfT^r'f 

1 1 1 1 1 1 

© 

id 


tt 

Chro¬ 

nom¬ 

eter 

No 

1823 

CO CD C H H H N I s * t'— t- t-» NNt'.NNh- 

cm cm cm co co eo co co cococococoeococcccco 

77777+777777777+77 

P* P- -4 »-4 >-4 

hhhNOM 

1—4 1—4 «—4 rH r—4 r-4 
++++++ 

CM CM CM 00 00 CO 
rf rr lO lO lO 

++++++ 

CQ 04 04 00 00 00 
up »r -r »C © tO 

r-4 1—4 1—4 iH 1—4 —H 

++++++ 

oooooor^r^r- 

N 1^ © C CD 

++++++ 

c 

© 

> 

© 

w 

Pres¬ 

sure 

t^cOeOt>-COOr»O^J , *-Hi-»COt^cO»O^J'CO*-^ 

++++++++++11++++++ 

+i+r++ 

CO ^ r-4 CO CO <N 

1+1+++ 

CO CO T CO 04 04 

1—4 1-4 

++++++ 

COHHHtf H 

+ 1 + 1 + + 

cr: 

C 

c 

•+. 


Tem¬ 

pera¬ 

ture 

MHNOOOiftCS'OMtOOOCH'XN'-'CO 

iHoxocoor^i-©*o^ , T}«uo©r-t'-i'-r-c© 

77 i i i i i i i i i i i i i i i i 

W^cOOmO 
rH CM CM CO CO h* 

++++++ 

+ 93 

+ 92 

+ 8S 

+ 87 

+ 84 

+ 86 

1-4 OO *r CO CO O 
0000030 

r-4 iH —^ 1—4 1—4 

++++++ 

CO CM O O tO 00 
CO Oi C CO to CD 

»—4 1—4 r4 l-H 

+ + + + + + 


Arc 

oooooor , *»oc-t'*t^t'-<ocoooi>-ojc*t>»ooc5t'» 

1 1 1 1 1 1 1 1 1 i 1 1 ! 1 ! 1 1 1 

t>- 00 05 00 00 

1 I 1 1 1 1 

Cioot>-oox a> 

1 1 1 1 1 1 

OOOOOOON 

r-4 r-4 1-4 

I 1 II 1 1 

00 00 CO CO 00 CO 

(Mill 

■s 

l 

c 

c 

» 

Chronom¬ 
eter No. 

1841 

8. 

0.5008585 
.5008566 
. 5008558 
.5006784 
.5006797 
. 5006792 
.5006416 
.5006425 
.5008398 
. 5006401 
.5006398 
. 5006419 
.5006427 
. 5006437 
. 5006447 
. 5006457 
. o006464 
. 5006418 

.5008454 
.5008441 
. 5006665 
. 5006646 
.5006305 
.5006344 

.5008376 
. 5008343 

.5006616 

.5006596 

.5006262 

.5006274 

Noroaopr 

lOrocMOn-T 
d d CM CM O C 
co X i - r- t- 
o o o o c o 
O QQOoo 
to to to *o to to 

.5008348 

.5008317 

.5006577 

.5006.532 

.5006138 

.5006138 

S3 

| 

C 

© 

P-. 

Chronom¬ 
eter No. 
1823 

8. 

0. 5008328 
. 500S309 
. 5008298 
.5006543 
. 5006531 
. 5006514 
. 5006157 
. 5006159 
. 5006119 
. 5006121 
.5006140 
.5006146 
. 5006155 
. 5006173 
. 5006162 
. 5006174 
. 5006177 
. 5006153 

. 500S245 
. 5008227 
. 5006450 
. 5006453 
. 5000090 
.5006078 

. 5008157 
. 5008147 
. 5006372 
. 5006379 
. 5006021 
. 5006008 

.500S037 

. 5008033 

.5006980 

.5006993 

.5006798 

.5006777 

.5008124 

.5008119 

. 5006323 

.5006300 

. 5005936 

.5005914 



i 

© 

s 

Jt^NNtDNOONOOQM’ttOtCOOOOHa 

^iTvkOLO>OtOtO>OtOiOCO!OCOtOiCiCtOtOvO 

HTC-H^OOH 
CO © © CO LO CD 

CfiOlTTOCOH 

CO to co co to CO 

05 05 OO 05 O O 

to to to to to to 

OfHif lOH 

CD CD CD CD O CD 



£ 

CO 

g 





Tem¬ 

pera¬ 

ture 

.COWHiOO^tCWOr-OlCCOOCOOCO 

^l>’tO^OCOt>iONOC) 1 -Tr^yOOC'MO 

ooaa'O’t' 

N O CO CM d O 

00 O r- CM © tO 
t^COOCJOO 

CO CO 1-4 CO N r4 

to -sr to to CD CD 

CM O H 03 H O 
O X TT 00 CO © 

0 t7 (7 p. p- n d c d t: 1 d d ^ c co «£ 

++++++ 

04 CM CM CM 04 04 

04 04 04 CM CM 04 

T—4 i-H IH 1—4 1—4 1-4 

HHHHHH 

© 

a 

Final 

J jiOCOM(N'tWNr-.CNNO>»C^WNiOOC 

^ r—4 i—4 h4 h4 h 4 rH **4 C“j rH »—4 h- 4 1—4 rH O 

co tp co to 

r—4 i—4 *—4 i-H i—4 

oo to cor-co oo 

1—4 1-4 l—4 1—4 i—4 1—4 

05 CO CO 05 05 CD 

HHHHHH 

h- © © N to N 

hhhhhCM 

cs 


l —. 

e *HrtHHC'iaOCCClO)(NONNONNH 
g iO iO >C »0 >C’t O >C ’T 'T <5 O lO 'C ifj lO ui lO 

ccr^ojco o os 


05 O O CO o to 

r- 00 H H t>- r-4 

&■ 



5.2 

Hi 

TJ4 TJ4 4^4 Tf4 Kii + 

tp + + + to 

4T to to + to + 

■»r tt to to tt to 

a 


Chro¬ 
nome¬ 
ter No. 

1841 

a>©waor4h.cccDr^©©t^cooNcoH 

©M©0)CO©H4CNO<NO>'«rXCOt^M© 

CM CO CM © lO CM 

cm © © © © co 

O^CMcCOO 
05 »-* rjt lO CO o 

oc r- OC O CO 04 
04 04 to CO to 

OO 1-4 CM 00 d Q 
CiCOHQCX 

s- 

C c3 

*5’-h‘c4c4cc + cooc;— 4*--*-4C505o6cot^t^o 
o 03 a © © o a </j o> c. q r. •>: cr oc cr. oo a 

CMD4D4COCOCOCOCOCOCCCOCOCOCOCOCOCOCO 

CO CO 1C CO CO + 
© © I s - P— 05 05 
CM <M CO CO CO co 

CO O OC 05 05 05 
Cl O N i^ 05 O 
04 CO CO CC CO CO 

CO + CD C'- tO tO 
O O if io to 
CO CO CO CO CO CO 

03 O O CO h- N 
© © CO OC o © 
CM CO CO CO tt TP 

© 

O 

a 

© 

o 

Chro¬ 
nome¬ 
ter No. 
1823 

W©C0O©00^C<04}4^O»C©O'<t(NC0© 

I^Mt^©CMN‘CCOOO>©N©>GCS , n , '-’t>' 

«oc5f-8i-4c4co + coo^cot^t^cd»ocd»f5^cd 
ooooooc. ooooooooocooco 

303.71 
304.36 
388.11 
387.90 
411.01 
411.82 

-4 CO CO I"- F-4 to 

O co oo co r- co 

0- t'- 04 04 tO CO 
COC5C5HH 
CO CO CO CO TT TJ* 

00 O Tt* o CO 00 

to r- co o cm co 

1-4 1-4 00 00 00 05 
r-4 —4 lO to CD CD 

co CO CO CO CO CO 

tt CM r-4 © CO CM 
CM tt © CO © CM 

oo oo to r- h co 

© © © © CM CM 
CO CO CO CO TT fr 

Date 

1909 

Nov. 4-5_ 

Nov. 5. 

Nov. 5. 

Nov. 5-6_ 

Nov. 6. 

Nov. 6. 

Nov. 6-7_ 

Nov. 7. 

Nov. 7. 

Nov. 7-8.... 

Nov. 8. 

Nov. 8. 

Nov. 8-9_ 

Nov. 9. 

Nov. 9. 

Nov. 9-10_ 

Nov. 10. 

Nov. 10. 

Nov. 26-27.. 

Nov. 27. 

Nov. 27. 

Nov. 27-28.. 

Nov. 28. 

Nov. 28. 

Dec. 2-3. 

Dec. 3. 

Dec. 3. 

Dec. 3-4. 

Dec. 4. 

Dee. 4. 

Dec. 2-3. 

Dec. 3. 

Dec. 3. 

Dec. 3-4. 

Dec. 4. 

Dec. 4. 

Dec. 8-9. 

Dec. 9. 

Dec. 9. 

Dec. 9-10_ 

Dec. 10. 

Dee. 10. 



1 

Posi- 

tion 

PQQQflQQfiQfifiCOfififlflfi 

OOQOOfi 

OOQOfifi 

AROfiOfi 

ORfiROO 

Pen¬ 

du¬ 

lum 

4}"tTiO>ClOCCCD©©©©©©CO©© 

Tj4 4?»OlOCtO 
-<<<<<< 

Tp *<p »0 tO © © 
<<<<<,< 

IT TT* to to CO CO 

nnccaam 

TT ft* tO tO © © 

U> 

&6 

&Z 

oa 

rHCMcoTno©r^oo©©»—CMco-tt-toor-co 

nHHMrlrtHHH 

rH CM CO tP tO © 

*-■ 04 CO to co 

© 

r-4 CM CO ”«r to co 

r-4 CM CO TP tO © 
•O 

U* 

© 

> 

o 

TJ 

3 

C 

o 

48 

<*9 

0Q 

Washington, D. C., 
Coast and Geodetic 
Survey Office, Wil¬ 
liam It. Burger. 

Washington, D. C., 
Coast and Geodetic 
Survey Office, Wil¬ 
liam H. Burger. 

Washington, D. ('., 
Coast and Geodetic 
Survey Office, Wil¬ 
liam H. Burger. 

Washington, D. 

Coast and Geodetic 
Survey Office, Wil¬ 
liam H. Burger. 

Washington, D. C., 
Coast and Geodetic 
Survey Office, Wil¬ 
liam H. Burger. 









































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


149 


S3 

is 

Hs 

Is 

s s 

© 0 

M 

ao© 

© 0 

£8 
rr © 

H M 
© © 

S3 

© CS 

Tf © 

pi© 

S *H 

© ” 

do 

C5© 

& + 

do 

S-H 

© d 

S-H 

©d 

55 + 

© © 
s + 

o> c5 

s + 

©OlOOfOH 
O 0 O O O rH 
CO CO CO CM CO CO 

© CM © © 00 © 
rH CM -H rH rH CM 
CM CM CM CM CM CM 

M O «C H N U5 
CM »—• CM CM CM CM 
HHHHHH 

t'- © © © r^© 
IO CO © IO © CO 

© © 00 ©© 

O N h CM CO CO 
CO CM CO CM CM CM 
©©©©©© 

© © CM CM hp © 
© © 00 f- 00 © 
©©©©©© 

<■ © © hp co © 
©©©©©© 
TP Tp Tp 4p rp rp 

© CM rH fs. rH rH 

© gec 00 ©© 

rn © CO f*» © 

© «o © © © 

OOOOOO 

000000 

05 05 O) O) 05 05 
N N N N N N 
C5 05 05 05 05 05 

05 05 O) 05 C5 C5 

t- r-- 

05 C5 C5 C5 C5 05 

© © © © © © 
r- r- r^ 

© © © © © © 

© © © © © © 
f'- r- f'- 

© © © © © © 

©©©©©© 
N N l> N N N 
©©©©©© 

©©©©©© 
N tr N N N 

©©©©©© 

© © © © © © 
r- r>. 

© © © © © © 

©©©©©© 
r* h* h* h. 
©©©©©© 

.5010413 
.5910430 
. 5008651 
. 5008668 
.5008301 
. 5008280 

.5010637 
.5010630 
. 5008870 
.5008880 
.5008518 
.5008501 

.5010883 
. 5010901 

.5009111 

. 5009122 

. 5008750 

.5008758 

.5011057 

.5011044 

.5011032 

.5009263 

.5009289 

.5008929 

.5008921 

. 5009827 

. 5009848 

. 5008072 

. 5008095 

. 5007732 

. 5007732 

.5009672 

.5009663 

. 5007942 

. 5007970 

. 5007582 

. 5007568 

.5010036 

.5010035 

. 5008264 

. 5008270 

. 5007918 

.5007909 

. 5010696 

. 50106S2 

. 5008968 

. 5008952 

. 5008587 

. 5008586 

. 5009992 

. 5010006 

. 5008272 

. 5008262 

. 5007903 

. 5007889 

.5010420 

1 .5010417 

. 5008636 
. 5008661 
. 5008303 
. 5008304 

.5010644 
.5010629 
.5008873 
. 5008874 
.5008522 
.5008495 

.5010877 
.5010905 
. 5009105 
.5009122 
.5008753 
. 5008772 
i 

.5011034 

.5011029 

.5011037 

.5009280 

. 5009289 

. 5008936 

.5008915 

1 .5009812 

.5009852 

.5008067 

. 5008094 

.5007740 

.5007744 

1 .5009656 

.5009672 

.5007946 

. 5007963 

.5007597 

.5007570 

.5010026 

.5010031 

.5008266 

.5008268 

.5007923 

.5007920 

. 5010702 

. 5010687 

. 5008975 

.5008955 

. 5008576 

. 5008581 

. 5009988 

. 5009994 

.5008281 

. 5008272 

.5007904 

. 5007894 

.5010106 
.5010443 
.5008666 
. 5008675 
. 5008299 
. 5008257 

.5010630 
.5010631 
.5008868 
.5008885 
. 5008513 
. 5008507 

O'. N N H X »p 
OOO hC 4 T rp 

OOXhhNN 

OOC5DXCC' 

r-4 rH O © O O 

OOOOOO 
IO 40 to © © c 

.5011080 
.5011059 
.5011028 
.5009246 
. 5009289 
. 5008922 

. 5008927 

.5009812 

.5009844 

.5008077 

.5008096 

. 5007725 

. 5007719 

.5009689 

.5009654 

.5007939 

.5007976 

. 50075C6 

.5007567 

.5010045 

.5010039 

.5008262 

.5008272 

.5007913 

.5007898 

.5010690 

. 5010678 

. 5008962 

.5008950 

. 5008598 

. 5008591 

. 5009996 

.5010020 

.5008262 

.5008253 

. 5007902 

. 5007884 

'f V ’T 

rH rH rH rH rH rH 

1 1 I 1 1 1 

OOOOOO 

1 1 1 1 1 1 

HHHHHH 

HHHHHH 

•11(111 

© CO © © CO © © 

rH »—4 rH hH «-H »-4 

1 1 1 1 1 1 1 

- 11 

- 11 

— 11 

- 11 

j— 11 

- 11 

CM CM CM CM CM CM 

rH rH rH rH rH rH 

1 1 1 1 1 1 

r>. t'r t>. r>. 

rH i-H rH rH rH rH 

1 1 1 1 1 1 

Hf Hf* H}4 

rH rH rH rH rH rH 

1 1 1 1 1 1 

©©©©©© 
rH rH rH rH rH rH 

1 1 1 1 1 1 

CM CM CM CM CM CM 

V rr 'T V T -r 

++++++ 

rH rH rH rH H 

05 05 05 05 05 05 

1 1 1 1 1 1 

lO >o iO 1*010 >0 
0 to © <0 C CO 

HHHHHH 

1 1 1 1 1 1 

© © © © © © © 
©©©©©©© 

7777777 

CM CM CM CM CM CM 

Tp TP Tp 45 * "* J 1 Tp 

777777 

CO © CO © © © 
© © © © © © 

777777 

©©©©©© 
© © © © © © 
CM CM CM CM CM CM 

1 1 1 1 1 1 

© © © © © © 
CM CM CM CM CM CM 

rH rH rH rH rH rH 

1 1 1 1 1 1 

V TP TP sp sp TP 
©©©©©© 

1 1 1 1 1 1 

CO CO CO CO CO CO 

H rH rH rH rH i —i 
HHHHHH 

1 1 1 1 1 1 

-rr -r -<r T -r rr 
lO 10 *0 to 10 

++++++ 

OOOOOO 

H rH H *-H rH rH 

++++++ 

CM CM CM CM © © © 
© © © © CM CM 

© CO CC CO © CO 
CM CM CM CM CM CM 

++++++ 

co cc co co co co 

r>- t'r r- i>. 

©©©©©© 

©©©©©© 

CO CO CO CO CO CO 

CM CM CM CM CM CM 

© © © © © © 
V Tp TP TT Tf Tp 

++++++ 

OH hPCM 50 cm 

TfHHNHH 

-h CO CM CO CO HP 
hH 

CM 00 CM © r* t-rH 

© HP r-t © © © 
rH 

CM tJ* © © © 

rH 

H H © O N TP 
rH 

©©rHrn ©CM 

© CO CC © © © 

++++1 

1 +++++ 

++++1+ 

++11+++ 

1 +++++ 

+ + + + 1 

++++++ 

1 1 ++ + 

++++++ 

+ 119 
+ 120 
+ 120 
+ 122 
+ 121 
+ 123 

CM iO b* tO 

iO »C iO ^ 'tp v 

HHHHHH 

CO CM CO 05 CM CO 
CO CO © © CO CO 

1 1 1 1 1 1 

M rl Tp © H © © 
rH CM © HP CM © © 

+++++++ 

CM 00 rH CO CM 

© Sh»©NC) 

rH rH rH rH rH rH 

1 1 1 1 II 

''SJSSSS 

© 00 © t^r © CO 
Tp tO 1^ CD N S 

cm© © ©or © 

CM©©l^tHfr 
CO CO CO CO CO CO 
++++++ 

+ 56 

+ 59 

+ 57 

+ 63 

+ 87 

+ 80 

»NOXOO 

rH rH 

1 1 1 1 1 1 

05 05 05 05 05 O 

1 1 1 1 1 1 

C5 C5 C5 O GO 05 

hH 

1 I 1 II 1 

©©©oo©oor- 

rH rH 

1 1 1 1 1 1 1 

© © © © CO © 

1 1 1 1 1 1 

00 CO © 00 00 CO 

1 1 1 1 II 

OO © © 00 © t'r 

1 1 1 1 1 1 

OOCOOO©©HH 

rH 

II 1 1 1 1 

t>»00©*^© rH 
rH 

1 1 1 1 1 1 

.5010181 
.5010175 
.5008393 
.5008417 
. 5008058 
. 5008065 

.5010606 
.5010583 
.5008825 
.5008838 
. 5008484 
.5008459 

.5011097 
.5011119 
. 5009344 
. 5009354 
. 5008972 
. 5008989 

.5011246 
.5011228 
.5011206 
. 5009455 
.5009481 
. 5009093 
. 5009067 

.5010171 
.5010188 
.5008405 
.5008441 
.5008073 
. 5008088 

. 5009787 
. 5009769 
.5008052 
.5008006 
.5007692 
.5007684 

.5010210 
.5010195 
.5008418 
.5008122 
. 5008079 
.5008073 

.5010536 

. 5010485 

. 5008759 

. 5008736 

. 5008350 

.5008357 

. 5010038 

.5010044 

. 5008334 

. 5008315 

. 5007924 

. 5007923 


S 8 oose eg < 

§ss< 


_ SciSfeS 

o lO C lO O lO lO IQ 1-0 >C lO 


*rOHiOOO 
CO CO 00 I — CJj 00 
COCOOOOCO 
O O © CO 00 00 

000808 

io <o 10 1C >o 10 


d © hhNI'. 
—1 C O © © 0C CO 

0008888 

UC lO *C iO iO iO *0 


(N (N N 1 C O 10 

CO rH HP l> O- © 
OOJhhNN 

© © 00 oc 

OOOOOO 

000000 

1C iO iO iQ >0 iQ 


hp I'- 00 CO t 
© © r- r^. 

888888 
1C IQ 1C »0 O lO 


co cm co © 00 © 

(O’TICOOOJ 

OOOOOONffi 

§ 0 00 co r>- 

88888 
1C 1C 1C 10 10 lO 


N WOOlO 


CCN WCOOO 
o w ic (>. 
CO 00 o o © © 

- 1 0C GO t-» I'r 

_J88S8 

LC <c ic »C *0 lO 


CO CO 00 © © © 
© © © © © © 

NhhOOh 
© © © © © © 

CM © rH © © 05 
©©©©©© 

rH © © CO © © CM 
©©©©©©© 

© © CO 00 CO CO 
l>- © © © © © 

rH © 00 Hp CO © 

© © © © © 00 

CM CM CO rH © 

©©©©©© 

© ©rH © 
©©©©©© 

00 © ©00 © © 
©©©©©© 

fT CO rH t'. CM © 
hhhOhO 

00 rH © t>. © rH 
CO CO CM © HP © 

h»NTp© NN 
00 h* CO N CO 

© © © CM rH 05 TP 
© Hp !>•©©© HP 

CO © Hp © © 00 
© CM CM © CM © 

N N a N CM 

—. np 10 © CM CO 

rH © © rH CM © 
© CO rH TP CM CM 

cm co © or © co 

CO HP CM rn © © 

r- © Hp oj cm © 

© © © Hp © O 

CM CM CM CM CM CM 

rH rH rH rH rH rH 

rH rH rH rH rH rH 

©©©©©© 

rH rH rH rH rH rH 

Tp rp CO CO TP CO CO 

rH rH rH rH rH rH rH 

© © © © © © 

© HP Hp TP Hp Hp 

I-H rH rH rH rH rH 

CO CO CO CO CO CO 

rH rH rH rH rH rH 

© © © © © 

co co co co d eo 

© CO tr © © © 

CO N N N N O 

00 

© © © t>» Hp Jn- 

t^©© 

© © © © © 

© © © © © CO 

© © © t>. ©rH 

CO 00 © © t*r rH 

HHHHHH 

rH rH rH rH rH rH 

rH rH rH rH rH rH 

CM CM rH H H rH rH 

rH rH rH rH rH rH 

HHHHHH 

hNhhhh 

rH rH rH rH rH CM 

rH rH rH rH rH CM 

rH © rH rH rH © 

rH rH © 00 rH rH 

© rH © © rH 

CO CM CO CO © Cr 

© © © rH rH © 

© t''* CM 00 rH hH 

© 00 © 00 rH © 

© © t^» rH CO CO 

C- © CO © rH CM 

© V © © © © 

© © rji Hp © © 

Hji © © HP rp © 

© © © © © Tp 

•O HP Hji © © HP 

>0 HP © HP © © 

© Hp HP HP © HP 

© IO HP © © © 

Hp © HP © © 

© ©©CM © 00 
© CM CO © t'r rjr 

CM CM 00 © CM 

CM I s - h* CO rH © 

00 Hp © © HP CM 
t > » CO © rH © 

©©©©©©CO 
00 rH © 00 CM HT CM 

© © CO © © rH 
CO © © © rH © 

HP CM © CO © TP 

co ht © hp *o co 

© CM O CM Ft © 
CO t'- © CO © rH 

© CM 00 00 CO 

l>- © © © 00 © 

hp rn or © CM 

© HP HP rH © © 

© ©‘ 06 © © 

Tp r © © rH rH 

CM CM CM CM CO CO 

© © CO CO © © 

CM CM CM CM 04 

© © 06 © 06 

CM (N O ^ 1- N 
CM CM CM C) CM CM 

CM CO CO *P © © 

(M !N CM C C N N 
CM CM CM CM CM CM CM 

© © © © © 
*T Hr © © r-< 

CM CM CM CM CO CO 

© © rH © © © 
•O © rH rH CM CM 
CM CM CO CO CO CO 

© © © © 
HP TP © © C rH 

CM CM CM CM CO CO 

cc © © © © 
CO co cc cc © © 

CM CM CM CM CM CM 

© oi d H © © 

HT HP O © rH rH 

CM CM CO CO CO CO 

r^. © © CM © rH 
co © © CO CO t r 

CM 00 CM © 00 CM 

rH CM © © CM rp 

© CM © © © CM 
CM CM t'* CO CM CO 

©CM00CMCM©r- 
l'- hp © CM © © © 

© CM 00 rH © © 
CM 1^ CO CO HP CM 

cm © 00 r- Hp hp 

© HT CO © rH CM 

© © hp © CM © 
00 © © HP 00 © 

CM © © ©CO © 
©CM© ©00 © 

CM © © © © HP 
©©CM© ©<» 

d © 00 CO r-H CM 

wr co co 00 © 0 
CM CM CM CM CO CO 

CM CM CM nr 

rr rr © © © © 
CM CM CM CM CO CO 

rH rH © © 00 00 

r>l 06 © <• co © © 
cm cm cm r>- 00 00 
CM CM CM CM CM CM CM 

CM CM h» © rH rH 

© © © © CM CM 
CM CM CO CO CO CO 

CM -r CM O © 00 
© © CM CM CO CO 
CM CM CO CO CO CO 

CO Hp © © -p © 
© O rH rH CM CM 
CM CM CO CO CO CO 

© t>» C^- 00 rH CM 
TTTf OfflHH 

CM CM CM CM CO CO 

© hp d d © d 
© © rH rH CM CM 
CM CM CO CO CO CO 

wji • • © • • 
rH • • *H • • 

2 c4 hj* -r © © 

QjHHHHHH 

§3 : :s: : : 

CM • .CO • . 

1 • • 1 • • 
rH CM CM CM COCO 

10 - 11 .. 

11 . 

11 . 

11 . 

11 - 12 .. 

12 . 

12 . 

17- 18.. 

18. 

18. 

18- 19.. 

19. 

19. 

5 ; IJ i i 
© © © © 

CM CM CM CM CM CM 

© J Ir^ J ! 
•A © © ci 

S : :2 • ! 

00 00 00 5 d 

hhhh h h 

CM . I CM ; 

4 . ©©’©©’ ©* 

CM CM CM CM CM CM 

a a a a q g 

rtJ 03 03 OT Co C3 

»-9 

a a a a a a 

c3 c3 a cc c3 a 

►-S h-j >-} t-5 l-S 

O O 3) CJ 11 <D 

£ fc, fit (i, fn 

X3 XS 

1 1 1 1 1 1 D 

M fc fl< + fe + 

U 1 1 1 1 ) 1 

++++++ 

11 c c c 0 c 

pH (Xt + ft, [i, + 

c3 o3 c3 c3 aJ 

sssssa 

u u> C u 

^ C3 C3 03 C3 C3 

ssssss 

L. k k. U U M 

C3 C3 d 03 03 C3 

ssssss 

ClOfifiOO 

QfiQQOQ 

QOOflflQ 

fiflOQQOO 

QfiQOPQ 

QOQPOP 

OQOOflfl 

RflOPOQ 

ROfiORO 

wp HJ* © © © © 

<j H H H 

TP © © © © 

<j <5 

HP -P © © © © 
<J<J<<<HJJ 

HP Hp -"P © © © © 

<j <!><<: c < h 

HP HP © © © © 
<<<<<< 

HP HP © © © © 
<<<<<< 

HP -P © © © © 
<<<<<< 

HP « © © © © 
<<<<<< 

Hp HP © © © © 
<<<<<< 

rH CM CO Hj*©© 

rH CM CO Tp © © 

rH CM CO Hp © © 

rH CM CO •••©© 

0 0 

rH CM CO HP © © 

rH CM CO TP © © 

rH CM CO HP © © 

rH CM CO HP © © 

rH CM CO Hp © © 


few 

II 


„ Q) 


8 «S 

oEh« 

fc 


y, >5 

CL) <D 

££ 

!« 

fij 

CM* Z2 

d* 

Z 


X S 
0) to 

o« 

(2w 

E | 

•23 

d£ 
5? u 


*5 

<u . 

&w 

50 

^ 03 



N S 

r4 »H 

03 ^ 

•C “ 

” Sf 

< 5 


m* 

I® 

0td 
a _ 



0 g 

s= 

0 

d^ 

6* 

Z 

Z 


(U o> 

2 n 

|W 

o g 
© d 


d£ 

z 


"C M 

<5 

•a" 

Sij 


fig 


d£ 

Z 


a M ‘ 

oH 

§ 0 

o* 

■ga 

gis 

o 


o< 

Z 


i 


a Simultaneous with B4, B5, B6. b First half swing only. ^Swings 1 and 2 were swings of 4-hour periods and the mean was used as a single swing. 














































































Pendulum observations and reductions —Continued. 


150 


U. 8. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


© 

S 


i 

3 


o* —* 
28 
OS O 


05 O 

05 "H 


OS O 
05 "H 


<y. o 

o* 


!DOCiiO'r(/)03N 

SJ2£72222i7 co 2 

J^jOS OS Os 05 05 05 05 05 C5 
^ r-~ m i- t -m r- 
^*4 05 05 05 05 05 05 05 C5 05 


CCrrosCOCSOOOCO^O 

OCO)05CCCO-H 

NC'IhhhNNC'IN 

05 05 05 05 05 05 C5 05 05 
i'- m t- r- i-'- 

050505050505050505 


Cl OO Tf t^» *C —< 

n /. co o 

lO O IQ *r. lO »C 
05 C5 05 05 05 05 
05 05 05 C5 05 05 


to '-t* CC Cl d 
OOiCOOb* 
l'J iO i(j i/5 iO 

05 C* 05 05 O* 05 
l- i>- m r - t -l- 
C5 05 05 G5 05 05 


• ••*.....••• CO O CO *C CO 05 

... CC CO CO CO d —* 

.(COCCOOO 

•••!*•!••••• OOOOQQ 
..OO OC TO CC -X OC 

• • • . • . « . i « • • 05 05 05 05 05 05 

C^M'CSCCCCOr^cOcOrrOS'rt' t>» eD 00 CO CD 

-r CD *-D -rf- O tD O CC d CO CO -h Cl *0 | CO 

COCOCgCgU^cOnocOC^CSClCS © © d d ©5 05 

iC O lO >0 C to to IT. lO lO lO >0 L"5 IG *C Id C V-. 


S 

£ 

*- 

u 

O 

o 

■g 

£ 

Ph 


© 

s 


■^MCOOOOCCOCC 1 
t'-«C05—•iO-'S'CI*—<—I 
t^h-OCcDOOtOO 

• oocoosqooocoooos 
<0000000 
ooooooooo 

L“5 lO lO lO >0 C O iO O 


iC H r/ N O V Cl O CO CO -+ *0 —< CO 

N M CO C5 »C V CC X CC © 'D *0 OC -H* 

!i) O OJ 05 O iO • O 7J t" CO 05 05 O CO 

O O CC' 00 X CO r X 00 X © 05 f- l- r- L- 

—< —icroocooo oooooo 
ooooooooo oooooo 

U5 lO *C lO lO O ^5 *c. o U5 us t5 iO 


OCX CO ^ O ^ 
u: 'C h x »*• *h 
r- o o o o 
c. ©. cr t - r - 

888888 
kC u5 >0 *C O 


C O 

r- ^ 

5 « 


r^N'J'CCOSNiOCOH 
COtOCOrdOCONN 
r^r^ooooocoo 
• oocscsoncrooooos 
22 0000 ^ 
ooooooooo 

tOtOiOOkOOkOtQiO 


O^M-hODCCMOJO 
CO Cl ’f CC >r.' o CO C 
COCOCVOOkOiOkCO 
C C «. » Yj X O) CO CC 

—• o © © © © o o 
ooooooooo 

C lO *C iO >0 ‘O u) »0 


O 'C' O P— ■*+ 
C5 CD C-kQ l-f- 

Noaa*-o cc 

§ C5 M t- t'- 

o o o o o 
o o o o o 
io u: kc o »o kC 


© d —< © —• d 
CD’t Cl f C 
Nf'OOC CD 
C5 05 00 I - 

888888 

lOkOiCtCiCkQ 


CO O CD *D QC C5 eo <_. 

§ CC O O o lO O Ol CN CN Cl 

SS8soo55§S§i§o 

kC kO IT) »C CO lO kO 1C >C lO lO >o 


O O 05 d C5 CD 
«—< cm *0 '-t -r 
OOMCIClOi 
t- t— OkC^2 

888888 

lOkOkCkO *C ID 


§ O, 


0>7» 

O >-00 

3-2-< 
6® 


CNCICJC50»^05kO 
CrcDCS—•©■rrdO — 
NN050CDCOCOOO 
•OOOOCSCOOOOCCCOS 

OOOOOOOOO 

k.CkDiOiDkCkOk.'JkOVj 


*OCOOtD*OCD*D©C5 
C r /.MCCC5^C5M'' 
' >0(-- * ' - 


05 C5 »o *o *o *o 


. _ . - - *0 00 

C O X CC CT 00 cr 00 oo 

--8888888 


iDHCJkOON 
CO d »-D *-C 00 — 

r- i- os o. *o o 

o o t - t^- r— £— 

888888 
•0*0 10*0*0*0 


C tCMOCO 
*o —4 oc cc ci 
t-NOOCD© 

cs os co r- t'- i'- 

888888 
*0 10*0*0*0*0 


t'* 05 CO *D d CO 00 H CO *t Hi** 
*r O >C CO I - O D rH CC Cl " CO 
MCOMM*ODkOCOCI«NM 

cooooocxoooooooo 

888Sllllll88 

*o*o*o*o*o*o*o*o»o*o*o*o 


'tdOSM’t^CO 

d co . *o —« cs 
O C Cl Cl c. c 
r-1 - »o *o — -r 

8 00000 
ooooo 
*c *o *o »o *o *o 


I 

p. 

1 

i 

•o 


CJ 

© 

> 


o 

1 

o 

u 


X © 
® £ 
+ 3 


ddddddddd CO CO CO CO iO CO —. r- —< — —< — dddddddddddd . 


I I I I I I I I I I I I I il I I I III!!! I I II I I 


I N It I II I II II II I I 


03 

tf 


6 • . . i" - 

t;S®0^ 

Oa® z 2 


co»coonoocconoocc 

I I I I I I I I I 


I I I I I I I I I 


r ' i - 1 - t- r - r' 

777777 


I I I I I I II I I I I I I I! I I I I I II I 


4 ' . ,M 
>- S <3 o N 

ggsz* 


ggggsgssg 

+++++++++ 


*o *o *o U J *o *o 


+++++++++ 


MMOflfllNNNCICIMN 

777+77 777777777777 


C£5 CO CO <0 CO tO 


+ + + + + ' 


w ® 

® t. 

P 3 

P. CQ 


OJ-.COCO^<lffl-.-H« cOuONeOCO—ccOOlOJ C CC -H f 11- W t-NCOOOlOlO OOOHVMCOOcO'fOO.': NiOOOWlOO 


++++ + 


+++++++++ 


L+ + 


++++++ ++++++ +++++ ++++++ 


S u | 

® © 3 
Eh C--*h 


to 1— d d *o CD « 

+77777777 


OCO^iOCOO-^OSkO 

*OCO*Orj*'^'^cOl'-0C 

ddddddddd 


- + + 4- 


++ I 


. .©coc. 

i— —i d d d 

I I I I I 



I I I I I I 


C0 35C5 0S00005-«f 


• OOOOO—*C5*—> —• —• O 05 00 C5 HHCO©© 


<C505OQ000C50G05C5C5C5 00 D D D O 0> 


i i i i i i i ! i it i i i i i i i i i I i I i i i i i i i t i t t i i t i i i i i i i i i i i 


£ 

L 

o 

o 

a 

3 

T3 

O' 

*n 

4> 

Ph 


So 

°{-C0 


*o 

*o o 


—• d OS 05 05 —• 
dd'TMHOd 
—< —• t— r >--h 

as os cr oo co or. os 
o 5 o o o o o 

I—, I—> —. f— 1 1 —I —> — 






05 O GO O -# »D 05 05 to 
O-* 0 C-*tDdOl-CD 
cOcCX©iflkO*D-^X 
OOCOCOGOOOOOX CO 

ooooSSooo 

*0*0*0 0*0*0*0 0*0 


lO O N H iC t' 
CDt-ODiOkO 
05 CO —• — 1 C» 50 

S OSCOCOt'-C- 

ooooo 
oooooo 
* 0 * 0 * 0*0 0*0 


C o 00 00 CD 00 

^ O O O' o 

OOOOOO 

*o *o *o- »o *o *o 


d d **C d O 2: d 05 to —« t- -r 
M T *r d X Q t' 00 I' D — 
NNNl^00 9C&OCOC o 

^njiOOCC'CioSo*. o 


cc co *o *o Cl d 

c- {>• *o *o *o *o 

888888 

*o*o*o*o*o*o 


Eo„ 

2zS 

Ofc.CC 

I- <L _J 

5® 


OcrdQtDOOOOCC 
^ccccoco5i^ccd 
tc*oc.cr^-^'c<*cct^ 
•OCOOOOOOCOOf'CCX 
Ot • O O O O O O O' 

ooooooooo 

* 0 * 0 * 0 * 010 * 0 * 0 * 0*0 


C5d—iiOCDCCCD—»o 
MiSOClOOeOOMr * 
d Cl *0 lO. —I — — c 

O O X no co 00 cc cr oc 

ooooooooo 

* 00 * 0 * 0 * 0 * 0 * 0 * 0*0 


N^MOOCCI 

*0 1— *o CO 

to cr co cr rf 

§ C5 

ooooo 
ooooo 
*o *o *o *o *o *o 


COO^^CCO 
—< co —• cr ec *o 
or cc -- c 

D5 05 CC OC' r^. 

oooooo 

oooooo 

*0*0*0*0 40*0 


OOODMNdOOOOOCC X 
tti^*o—- csdo—itooccro 

rfTr-r-— CDC-CDl^-COCOCrcr 
00 00 QC OC CO CD CD CD CD tD O tD 

88888S8S88S8 

*o*o*o*o*o*o*o»o*o*o*o»o 


*•1 CO d d M/3 
•o O C O- TT —• 

o o cr d cs os 
t - r- *o *o •— 

888888 

10 *0*0*0*0*0 


Pres¬ 

sure 

•*O'*f < ^*tD00l'-—«COD 
gOt»*0*0*0»OCDCD*0 

OcDCC505dCOO 
*0 *0CD*O*OCDtDCDtD 

co *0 d —< c -f 

CD CD CD CD t -• CD 

d d *-• CD 00 05 
*0 CD CD *0 *0 kO 

'-rtOCOO — CCrrOCOO©-• 
*D*OCDCDCD*OCD*-OCDCD»OCD 

d 05 CD O 05 ^ 
CD *0 *D CD *0 *D 


|g§ 

_.^r^*ocD*-r*»05i^r-^ 

^)*OCOOC5CDdOO*0 

—irt*-+05dtDC0Crd 
00CCC5—‘dCC'-COd 

CD —< Ci M —• d 
G N h- O *C N 

M-©dHkCd 

CNONCCNrj 

CO^H*C050^rcDdCOt-Hl'-Q 

OCONtrrriOCJ’Hh-^rC® 

—* -*r *0 0 0 r>« 
—4 —h r>» co —4 os 



O WdClHH-iH-H 

OC 00 OC 05 05* 05 00 00 OC 

*0 *C *0 tD 

05 ©5 05 C5 05 O 
—• H H H — 1 d 

050050500000-4 — 0 

—'d—4r-4dddddddd 

OC CC CC OC cc t-* 

0 


^*ooot»*o*oo*oooo 

OOOOCOOt^OOC5iOC5 

DCt^OOiDN 

H 0 OO ©Nf» 

WNNOtCONCDM»NN 

*ONNN DO 

H 

03 


J-4—•—•—•—'—<d—l—«d 

d—l*— 

—' d —• —* —* —• 

d d —< — ^ —• 

d—«-4d—4— 


■p 

© 


g©HOdOHd*o^ 

NddWW’J'^dCO 

d^dGCi O 

d CO d C5 © t>. 

f-i0CCCOCC»00t>-00 0CO05 

h»XOOXN 


fl.2 

HH +-S 

gTT*0*0*0*0*0*0*0*0 

40*0*0*0*0*0*0*0*0 

*0 *0 *0 *0 

*c *b *0 rt* *D ^ 

*0orr*0'7'r*'rr'j"4ro0o 

rr *C *0 rr rr 

1 

a 

Chro¬ 
nome¬ 
ter No. 
1841 

CDCON’taOCOO 

c^r^-cD*od*oco*ocD 

^dcodooocoood 

-HOt'D-CNdCCrf 

CD-OCVO 
CO CC 10 N X N 

or oc- cd co 05 *o 
05 —. to —« d 

*D<D—4^54CDQCOO—8CD05CD 
+ + + HCOTT ridHdr l" 

OOQCh CC Ol 

1 - CO -4 M 

© 

O-— 

C 05 
<s> > 

cr cs^^cD’cDt^t^^ 
d d r- i>. 00 oc cr or) r- 

ddddddddd 

COCCrn OcicC’tkO CO 
CO CO 00 GO 05 05 C5 05 OC 
ddddddddd 

—• co *0 *0 d cc 
*0 10 0 c d —* 

ddCOCOCC CO 

CD d 00 T-I f-H 

’* + ©©-'- 
d d d d co co 

r- co co i-‘ x r7 d 00 co *0 *0 co 

OC OC OC' OC' *0 *0*0*0Nt>NN 
ddddCOCOCOCOCOCOCOCO 

—• —1 1 ^. 05 00 CD 
+’ +• ■+ T h* 

CO CO -r rf T+ •— 

2 3 

a -w 

I 

0 

O 

Chro¬ 
nome¬ 
ter No. 
1823 

CDd00OddOQC*O 
tf DrtDcOiHDdO 

dkCQCThD^ocrc 

t^CO*Ol^GOC5O500t>. 

cr *0 2 * co cr co 

MkCOOCOO 

co d d 00 —« 
H cc d d *D —4 

OiCkOxTO + f-ir^tDCDdCC 
l-CDCO-O-O— 1 —4CDOXCCO 

-T* — CD O CO <D 
OC -T C5 05 CC © 

*o*ocD*o^tDcroro5^ 
co co x cr 05 cs 0 05 v? 
ddddddddd 

co^^cdiOi^crDit^ 

trtoacocc© 

ddddcocococod 

os 0 00 r7 «o ■*»* 
*o cD > co co 

d d CO CO C«C CO 

*0 00 Cs CO CO 

*0 *D 0 C d d 
d d co co co co 

to »o d r7 -r d’ — d co —< —4 co 

C5 C5 C5 OS I'- 1^- CO C5 05 O 

ddddCOCOCOCOCOCOCOCO 

'rr 4-r —< d «o cr 
>0 ».o r- r- © 0 

CO CO -4T *D *D 

Date 

1910 

1-2. 

2. 

2. 

2- 3. 

3. 

3 . 

3- 4. 

4 . 

4. 

d *. ’.co : jj* ; 

1 . • 1 • . 1 » . 

CO * rj* ' ! 

d : .d : . 

d co* co’ co -r ^ 
d d d d d d 

d 'c3 * * 

2 ; is :; 

Tf* . • • « *0 »N . . CD • 

d**..d'd**d. 

co-t-r^-r>-'— — *DtikO*o*A'0 
dddddddddddd 

CO I Jo * I 
d . . d • J 

r . . 1 • . 

dcococo*- — 

d d d d d d 

P- P* p. p- P* p. p. C- P* 

P.P.P.Q-P.P.O.C-P. 

1 * i- *7 1 -! i7 *7 

P.P.C.P-C7PL 

^ U t! u h>5 

P-P-P.P rt ^ 

to >. C>. >. >1 >-. >> >. >. 

c3c3c3cCc3c3c3c3c3c3o3c3 

© © © © © © 
C G fl p G C 
3 3 © © 2 3 

(-5 *-3 ►— >-5 

s| 

OftfiCfiflOCP 

OOQQOfififlfJ 

ccaccQ 

fifififtOfi 

fiocaoooooona 

QfiOOCC 

Pen¬ 

du¬ 

lum 

Tf-t<*O*OCDCDt0cD*O 

-t«"rr*OiOCOCOCDCO*0 

Tji -r *0 *0 CD CD 

rf *D lO CD CD 

*<■<<<;*<•< 

'*-r , rr'^rxr*0*D*0*0tDcDtDcD 

*t •+ kC *c «c c 

■< <! <J <! <1-«! 

tkC 

36 

ZZ 

0 rj 

«-Hdco-**otoi^ooas 

*HdWTt<kO©l»COOJ 

rH d CO -*J* *0 tO 

—' d CO Tf ID CD 

HdHdM^DO*OtONOO 

—4 —4 

r-l d CO Tf *0 CD 


> 

1 

o 

X? 

§ 

c 

2 

c3 

-M 

xn 


ztri 

dc 

"5S 

l*c 

£ r S 

f' k £r 

oS + 
St 


za 
? E 

tc rz 
CD 

>3 

. 

h-3 u 
. © 

c*l& 

®Scs 

S', 


Jew 

gK 
U — 

s s 

5= 

ro§ 

. 

K © 

r si 
& K h 
1 © 3 

sh« 

St 


75 

§« 

|w 

«l 

Kr ^ 

oi? 

Sr, 


tod 
O +3 £ 

fill 

a'ocoo 

fi 03 
a-*-* g 

2 O 3 rt 

^ucoa 


> 4 

•W4 

K2 

al 

E33 

p-g^ 

‘d§£ 

St 




























































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


151 


So 

ic 5 

§3 

H* rH 

gg 

00 0 
m g 
r>- 0 

£8 
x 0 

*•4 

w s 

88 

f $8 

$A 

OS i» 

0 0 

OO 41 

ft T 1 

OO 
ft *H 

do 

00 M 

ft ” 

82 
ft Tl 

i% 

8 ° 
ft Ml 

do 

X 11 
ft Ml 

00 X ft t'— CM CM 

Os ©- OS ft Os ft 

40 40 40 >0 40 10 

«wn»h»cn 
r_^ cc cc 0 

ft r>- x co ft ft 

CM CM Cm Cm *-h *-h 

X CC to X X CO 

4CNftOC050 
co co co co co 
h- N h- I'* f- 

O C ft X ft ft 
xxi^i-i-r^. 
CClCCftCCO 

CM g tO O CM ft 

CM CM CM CM CM CM 

ft to to to ft CM 
888888 

OOONtO'fCWMNl'NNNlQ 
X Cl X CM CM CM x Cm cm cm cm cm Cm cm 

I s — (— I s — t - t— f— (Na 1 — (S I s * f ^ 

S x «! 2 2 2 

ft ft ft ft ft ft 

dodddo 

X X X X OC OC 

ft ft ft ft ft ft 

0 0 odd© 

00 OC OC oc cc 00 
ft ft ft ft ft ^5 

oodddd 

X X X X X X 

ft ft ft ft ft ft 

dodddo 

X X X X X X 
ft ft ft ft ft ft 

dodddo 

X X X X X X 
ft ft OS ft ft ft 

oooodd 

OC X X X X X 
ft ft ft ft ft os 

ooooooooooddddd 

X X X X X X X X X X X X x X X 

ft ft ft ft ft ft ft ft ft ft ft ft. cs ft ft 

.6007103 
.6007112 
. 6005347 
. 5005354 
.5005017 
. 5005016 

. 5008190 
.5008188 
.5006453 
. 5006443 
.5006107 
. 5006103 

.5007024 
. 5007031 
. 5005280 
.5005289 

.5004948 

. 5004951 

O CO CM t rr CM 
t© rr ft ft rr rr 
CO«50®I'*N 

XT'? • O O 

888888 

40 O 40 IQ 40 IO 

tDN»f Nh-N 
ft ft TT ■'T ft ft 
aooHHi^N 

O O O tO rr 

808 S 80 

to to to to to 0 

O X O O tO CO 
ft ft X TT X ft 
O O X X ft ft 

X X CO cc to to 
OOOOOO 
OOOOOO 

to to to to to to 

.5008282 

.5008293 

.5007260 

.5007260 

.5007083 

.5007075 

.5006768 

.5006793 

.5005015 

.5005021 

.5004676 

.5004680 

.5004664 

.5004683 

.5005032 

.5005021 

.5006784 

.5006777 

.5006777 

.5006788 

.5005028 

.5007098 
. 5007108 
. 5005352 
.5005351 
. 5005017 
.5005024 

.5008183 
. 5008185 
.5006449 
. 5006431 
. 5006099 
.5006113 

. 5007030 
. 5007040 
. 5005279 
. 5005285 
.5004942 
. 5004952 

X X X —4 CSX 

XT M ft ft CO ''T* 

O Oft ft 1 ' 

888811 
40 4Q 40 *0 40 40 

.5006888 

.5006890 

.5005155 

.5005144 

.5004793 

.5004804 

.5008077 

.5008095 

.5006334 

.5006344 

.5005981 

. 5006006 

C^r ccCN’f 

O f- ft ccccxt^ 

2 : cm ci ^ c 00 
CJy.Cf NNNN 

^888888 

CM to tO to to to »0 

1841 

.5006734 

.5006780 

.5005009 

.5005021 

.5004672 

.5004692 

.5004653 

.5004684 

.5005053 

.5005029 

.5006782 

.5006795 

.5006778 

.5006788 

.5005037 

.5007109 
.5007116 
. 5005342 
. 5005357 
.5005017 
.5005007 

. 5008197 
. 5008192 
.5006457 
. 5006455 
.5006115 
.5006093 

. 5007019 
. 5007023 
.5005282 
. 5005293 
. 5004955 
. 5004950 

.500'653 
.50046 3 
.500 988 
.500 996 
.5006750 
.5006737 

.5006903 

.5006901 

. 5005134 

.5005150 

.5001801 

.5004790 

. 5008102 

.5008102 

.5006325 

. 5006335 

.5005989 

.5005987 

1589 

.5008294 

.5008291 

.5007255 

.5007261 

.5007079 

.5007076 

1823 

.5006801 

.5006806 

.5005021 

.5005022 

.5004681 

.5004669 

.5004675 

.5004683 

.5005010 

.6005013 

.5006787 

.5006760 

.5006776 

.5006789 

.5005019 

fH fH rH fH *—1 rH 
HHHHHH 

1 1 1 1 1 1 

ft ft ft ft ft ft 

1 1 1 1 1 1 

00 00 00 CO 00 00 

Mini 

OOOOOO 

f—1 r— 1 fh rH 1-4 F-H 

1 1 1 1 1 1 

ft ft ft ft ft ft 

1 1 1 1 1 1 

OOOOOO 

i 1 1 1 1 1 

CM CM CM CM CM CM 

fH r4 r4 rH M rH 

1 1 1 1 1 1 

oc 0000000000000 

HHHHHHHHHHHHHHH 

1 1 1 1 1 1 I 1 1 1 1 1 1 1 1 

ft ft ft ft ft ft 

V 'T 'T ^ 'T ' r T 

H H H -4 H r-t 

1 1 1 1 1 1 

oScCCtD 
CM CM CM CM CM CM 

1 M 1 1 1 

4C 40 »0 40 40 40 
CO OC CO X CO CO 

777777 

r— r^-t— 

X X X X X X 

777777 

OOOOOO 
O CO CO CO co CO 

777777 

CM CM CM CM CM CM 
I s * I'"' l— 1 "■ «>• 

•“H •—4 r-4 r ~4 *—4 r—t 

1 1 1 1 1 1 

Ssssggs 

^4 CM CM CM CM CM CM 

M++++++ 

T ^4rrr , q , 4-TrH’4rrr'H'H < 4yH’'44’TrH4 
^ rH rH rH i-H •—t *—4 *—4 *— rH rH rH rH rH rH rH 

- 1 1 1 1 1 1 1 I 1 1 1 1 1 I 1 

06 + 

06 + 

06 + 

06 + 

06 + 

06 + 

ft ft ft ft ft ft 
40 40 40 40 UQ lO 

4* + + + -h + 

10 40 40 40 40 40 
CO CC CO CO CO CO 

rH rH rH t—4 F-H rH 

-f + 4- + *f 4“ 

X X X CC CO cc 
i'- 1 " 1 ^ i>- 

++++++ 

OOOOOO 

X X X X X X 

++++++ 

OOOOOO 

X X X X X X 

++++++ 

ft e 

^Tftft rf XXX 
WM'OOKiOOCO 

H 1 1 1 1 1 1 

*+++++++++++++++ 

rH X ft CM CS 

rH 

10 -IP 10 ■»»> 

CO CO CO X to *H 

rH CM CO rr tO X 

NOrrh-NH 

hiDNhwO 

r-4 r-4 

PJWNlflON 

HH *-4 

■vMfNcctO’frNr-TTNtoor^iov 

++++++ 

++++++ 

++++++ 

1 +++++ 

1 1 1 + + 

+ + 1 1 + 

++++++ 

+++++++++++++++ 

i» ft co ft 00 

X iO »0 X rr rr 

W •«" 'T ^ V Tj< 

1 1 1 1 1 1 

<OtT'(P©© t^ 
*—4 H 

++++1 I 

00«H4«Ht>. 
*H M CO CO CO CO 
CO CO CO CO CO CO 

1 1 1 1 1 1 

X X rr ft X X 
X *0 CD 4f3 sr rr 

f-H fH F-H f-H *—4 1—4 

1 1 1 1 1 1 

rrCCCDCMOh- 
to t to CO CO to 

1 1 1 1 1 1 

NsrO-XO 

rr wr to to tO tO 

rH ^ r-4 »-H •—4 rt 

1 1 1 1 1 1 

to Cl 0 CO O CM 
X X X rH d CM 

TT TT TT TT 4j» 

1 1 1 1 1 1 

rHHj-ftftH-OOXOft—HCCcpCMrH 

NiO'fWMfiNwDJMWNNHji 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

CM ft ft O 00 ft 
fH rH 

1 1 1 1 1 1 

00 CO 00 ft CC ft 

1 1 1 1 1 1 

CC ft ft OX -r 

Mini 

© ft fH ft ft ft 

f-H rH 

Mllll 

ft OX 0 ft X 

»— 4 

1 1 1 1 1 1 

ft ft ft ft ft X 

1 1 1 I 1 1 

4—1 ft ft O rH O 
TH rH r—4 •—< 

1 1 1 1 1 1 

OOftftOftOXftftftrHftftO 

rH rH rH rH rH rH 

1 1 1 1 I 1 1 1 1 1 1 1 1 1 1 

. 5007716 
. 5007727 
. 5005975 
. 5005968 
. 5005632 
. 5005632 

. 5008438 
.5008444 
.5006719 
. 5006699 
. 5006379 
. 5006392 

. 5007546 
.5007547 
. 5005809 
.5005817 
.5005469 
.5005482 

.5005041 
. 5005007 
.5005364 
.5005352 
.5007083 
. 5007096 

. 5007127 
.5007117 
. 5005392 
. 5005392 
. 5005029 
. 5005037 

.5008414 
. 5008425 
. 5006677 
. 5006697 
. 5006319 
. 5006346 

2490 

.5008436 

.5008455 

.5007437 

.5007427 

.5007254 

.5007245 

1841 

.5006935 

.5006965 

.5005189 

.5005197 

.5004845 

.5004851 

.5004806 

.5004832 

.5005212 

.5005184 

.5006941 

.5006950 

.5006930 

.5006938 

.5005208 


OC X X X CO X 
ogftCNXftlj* 
•v rr t— t- X OO 

(•. o >o io o 
cooc88 

40 lO *G ‘O 


ococobB 

KXOCOiO 

838888 


lOONiOWO 
.-. fh ft O X X 

(NCMTOrHH 

M. 1 OO 1 C X 

S O ooco 
00000 
loiooidioo 


C (N N I^rr o 
a: - ooicotN 
COOCU'I' 


Nhh CO t — CO 
OTXOTCO 
X CO o h I' I' 
C O *C 10 >t TT1 

§§8883 

iO O iO 10 10 »o 


t'OOO'O >0 

CO CO <0 00 CM CM 
HHOCOOO 
00 00 X CO X CO 
000000 
000000 
10 X lOOiOlO 


ft rj r? c<5 cc C O 
TZ CO 00 t'- t > - CO CO 
CC Xj X N N !>. N 

‘■“ 888 

40 40 >0 40 lO ‘O 


2 s 
“ tO 


15 ^ ^ <O500^CMCO 

wd-«ClO)h-40 40ioOOCCCOiOOH 
’•.M^C5O5iOiOiOiC00XC<CCcOQ 
W ^ C TT W ’T W *r »r *^5 <c C -T 

®8S8S8S888S888il 

^404040404040 40 40404040 40 404010 


n* X O co X O 
to to CO to CO to 

CO X ft X ft CO 

to to to to to to 

rH CO CM X O X 

co X CO X co X 

X CM rH 0 ft f-h 

CO X O CO X CO 

f-H x X FH h CM 

r>- x x t"» x x 

X ft X X rr 

X X X 1-- X X 

h CM cc 0 XCO 
to X X X X X 

OOCMI'-GCftXXftXOCrr.OOOft 

xxxxxxxxxxxxxxx 

r* <N O OO O 

CO CD rH <0 to rr> 

CO CO ft X rH rH 

O CO h ft ft •3’ 

CO rr ft ft X O 

HHMC5Htr 

rr ft i>- rr rr 

X rr rr X X X 

CM H X rr rr X 

CM X ft 1-4 X CS 

X rr X X l"» X 

00 O to CO £4 00 

X X CM ft c 0 

ft ft CC 00 X CM X X CM ft X —r CM X 00 
(OCMHHOMOiCNONCOXlOO 

to to to to to to 

CM CM CM CM CM CM 

rr rr rr -r tO O 

rH rH rH rH rH rH 

CM CM CM CM CM X 
CM CM CM CM CM CM 

ft X* X X* X X 

H —H F-H H —H •—4 

x d d x d x 

rH *--4 H »-H fH f —1 

OC X 00 X X X 

»o x X *** x X 

CM CM CM CM CM CM 

xxxxxxxxtdxtdtdtdxx 

rH rH F-H »—4 F-H —1 T—4 »—( F-H f-H •—< F-H F—< ^H F-H 


to co co i>- x 

XNt'-XCO 

NNC5CiONft 

tH ft X ft ir. X 

X X tH (>• X X 

0s r^oo ft 0 i-H 

NNNNONOOOKNNONNO 

pi n t-t 

r—4 rH tH rH rH rH 





rH rH rH H CM CM 

HHHHhHHHHHHHHHN 

if}XOOh-C> 

ft r- x 0 ft 

ft rH rH X O CM 

XOCNhhN 

OhOhhOI 

rH ft »-H f-H X O 

MHOHlfO 

M«hhOOXN005COXC5HH 

to rjH to to ^ ^ 

rr HT rr to ’■'T rr 

rr X X X X X 

id rr X X X rr 

x »d td td *d rr 

X rr x td rr X 

to tO rr to X X 

xxxxxxxrrd*rrrrtdrrtdx 

O X X »0 O 

CO X X O X ft 
l- tO to I'r X tO 

O X CO CM X rr 

x r-r- x x x x 

rr X ft X X O 
rr X X X rr X 

OXXftftX 
COI-HHlOtr 

rr X O X X X 

X CM ft r->- h rr 

ft CM CC r>» C rr rr 
^OOmChhiO 

-^XXOQXftOOXtoOrrXCMXTrr 

^JftrrCMXrrOOXftOltH.XCMCMXrr 

rr rr X ft ^ ^ 

CM CM -4 rH rr 

co « 

cd co CM X CM* -H 
ft ft ft ft 

CM CM XX X X 

hhOO^© 

X X X X X X 
X X rp rr rr rr 

d ft d rd x cm* 

ft ft X X X X 
rr rr rr rr X X 

h h -r r MO 
to X X X ft ft 
X X rr rr rr rr 

Cs ft r— t'- ft ft 
CM CM X X X X 

HOCOfCNtdiO 
■A ft ft X (X rr rr 

Nnnmxcoco 

QrdftCMFHXtddr^doiddrHCQ 
^OIOCOCT. HHOl— xcoxxxxoo 
^XX rrrrxXXX'VrTXXXXrr 

to 0 0 x 0 

rr 0 O rr rr M4 
X ft rH ft to 

CC CO T rr rr X 
ft CM CO CO X O 

X x x 00 rr» rr 

OftSOtrfrCM 

rr X X X X rr 
X ft rr x fh r>- 

x ft ft x rr x 

t>- ft H ft rr rtfl 

ft O X CS rr xo 

Xz 0 cm x r- rr rr 

ftX^’XOOxXH-Hl^.CMxrrCMXX 

^N%H4pNOOOSi04riOCOH4jFNc*) 

x X X x 0 co 

rH r-4 d CC d 

H H C5 O rH C-l 
X X X X rr rr 

d f - X rr d X 
rr rr X X X X 
X X rr rr rr rr 

rr 00 d d —4 CM 
KCCOONN 
X X X X X X 

x td cm ft rd 00 

X X ft X CM CM 
X X rr rr X X 

NN^Hidd 

C O ft ft rH rH 

X X X X rr rr 

rr -V H H ft ft 

GO OQ CM CM CM 04 
^ CM CM X X X X 

QnCMCiocofdftftftrHi-Htdr^xtdcs 

”:r>.»>.ocHr'H* i *THrrHFHr^i-i>-r-.o 

^xxxxxxxxxxxxxxx 

» 1 • • • • 

»••••• 

• ••••• 
*? ! tT • • 

CM XXX 'tf 
►> >S >4 

3‘33'3’2'3 

hlh3^-5^n>-5 

July 11-12... 

July 12. 

July 12. 

July 12-13... 

July 13. 

July 13. 

July 19-20... 

July 20. 

July 20. 

July 20-21... 

July 21. 

July 21. 

July 27-28... 

July 28. 

July 28. 

July 28-29... 

July 29. 

July 29. 

Aug. 3-4- 

Aug. 4. 

Aug. 4. 

Aug. 4-5- 

Aug. 5. 

Aug. 5. 

Aug. 10-11.. 

Aug. 11. 

Aug. 11. 

Aug. 11-12.. 

Aug. 12. 

Aug. 12. 

Aug. 18-19.. 

Aug. 19. 

Aug. 19. 

Aug. 19-20... 

Aug. 20. 

Aug. 20. 

Aug. 17-18... 

Aug. 18. 

Aug. 18. 

Aug. 18-19... 

Aug. 19. 

Aug. 19. 

Aug. 19-20... 

Aug. 20_, 

Aug. 20. 

Aug. 20-21... 

Aug. 21. 

Aug. 21. 

Aug. 21-22... 

Aug. 22. 

Aug. 22. 

qqqqqq 

OfiOOOQ 

ROQQfiQ 

OORQQO 

popoao 

OQOOOfl 

QQCQQQ 

RQRQCQQQQQQQQQO 

rr ^ to to CO CO 

rj <! H <! H H 

rr rr to X CO CO 

<1 Hj < ■< H <1 

rr rr x X cc cO 

H H <1 <1 <5 <! 

X X X X rr rr 

rr rr X X X X 

rr rr X X X X 

H H •< H) Hi H 

rr rr X X X X 

pcaoscccaca 

rrrr»0*OXXXX»OXrrrrrrrrX 

«««««««< 

H««roe 

rH CM X rr X CO 

HCM X rr XCO 

H CM X rr XX 

cm x rr x x 

—H CM X rr X X 

H CM X rr X X 

HNXrriO®NOOOOHM«n<U5 

rH —1 H F-H fH h 







. 




M 

OS . 

Q be 

Isq 

*2 I 
©« 


«a 

s© 

H CJ 

!lW 

CQ 

<c JSf 

” -S.S 

cQ« 

55 


©P 

•-H 

o 
e S 

®w 
W - 

b .*3 be 

fc §3 
ds3 

55 



o 

5 bfl 

■O 

«a 
®w 
s ? 

Oft 

P-a 

»o 
*'■ a 
0 = 
25 


o a 
tisg 

£S> 
■§S* . 

£ .*£§• 

0’S 3 
-• aW 
SB . s • 

dfi«« 


Ofl 

°P 

03 

•<2 

sg i 

dW 


a Mean of the two rates. 







































































































Pendulum observations and reductions —Continued. 


152 


U. S. COAST 

AND 

GEODETIC 

SURVEY 

SPECIAL PUBLICATION NO. 




CC «-> 

H 



<* 

a8 

fCg 

X Q 

o> 0 

x 0 
too 

a 

S 

© 

b> 

C 

a> 0 

S-H 

01 *> 

oi O 

s-« 



g 

- 

© 


fcCC NNt' ~ 
Ci 05 05 05 0 

5 >oi oi ci oi oi o 

rs N N t>» t'* N N 
O C ® C 2 Ci Oi 


CO *C 


X X 1^* •-* »-* 

x t x ^ 
n- 


Cl Ol Cl Ol Ol Oi 
n- n- r - 

Oi Oi Oi Oi Oi Oi 


Ol Oi Oi Oi Oi Oi 
h* t'* N N t'* h« 
Oi Oi Oi Oi Oi Oi 


f-tWOO^-iOO 

x x x x oi o x 

iC 1 C 1 C »o *0 o 

cdodcoo 

cc oc oc a. cc ca_ x 

Ci Oi Oi © Ol Ci © 


NO^OOCO 

HHrrioOiO 

p* t— oi ci *o to 

- CC CC C-- 

*i o o < 
o o <__ 

10*0 10 * 0*0 0 


CONCT'OiO’f 
C’—‘CO*COCi 
CM CM *C *C O * CM 


10*0*0*0*0*0 


- r N tc CO C (M 
c^Wt'-xci'rr 
OCKCC^hh 

§ *C *0 *C U- t-> 

gggggg 

10*0*0*0*0*0 *0 *0 *C *C *0 *C *0 


_■ CO CM oc 00 

cc cc Ci © *r. tc 

-iced 

'555 


r *OTro*occOOL . _ 

S X' v 'r'^rttOtOCC'tO*C'l 

X X X OC CC - x $ t c 

gggggggggglg 

* 0*0 0*0 *o *o *o * 0 * 0*0 >o *o 


CC Tf N oc oc *c 
r h :>j Oi o 

PI CM CM CM c © 

x x t'* u- 

S s 2 S § 2 

*0000*0*0 


S o* H 

° *- GO 
u» © 


OlXNNMO 
OO-r-'TO—' 
N N O C5 c o 

^iooool 

o o o o o o 


lOHifOOtOCO 
Cl »-« CO X *-• 
t—* CM O O CM CO 
h*NNNCi© 

gggggg 

o o o o o o 


X cn -r- O O O —* 

S ci X Oi co V r 
Ol«WHHH 
~ rr *0 ‘ONNN 

gggggg 


tO t-4 PI »C «-• O CM *. 


V* 0 *CtO*C(NCiC?!MM 
COCOXCrCOCOOOtOCM 

x cc cc c/ cc x tctotc 
ScoccSScc 


- . wrx 
*X> CM P 1 CM 


C O CM Ci CO CM 
r-> r-. -rr r— oi 

50 to Oi Ol o o 
X X ec CO cc cp 
ccccco 

OOOOOO - - _____ - 

0000*0 0 0 0 0 0*000 oooooooooooo 


^ cm j 5 CM dk 
CM CM CM CM o Oi 

x x t- 1 - -c 

ggggge 

1/300000 


CI 


Chronom¬ 

eter No. 
1823 

s 

0.5008725 

.5008711 

.5006945 

.5006952 

.5006578 

.5006607 

.5007218 

.5007214 

.5007532 

.5007551 

.5009305 

.5009270 

N^OtONCJ 

c a in n a n 
0 tc 01 w »c *0 

OCOGOtOOtO 

gggggg 

*0 to *0 to tc tc 

.5005024 

.5005050 

.5005370 

.5005383 

.5007146 

.5007120 

.5007144 

CMcoc©tc , r>Oixr^N-*'5'-'Wi 
*C*OX*C*CX*—*—XCNr 

S 8 S 8 SS§SSS 8 s 

*CtCtC*CtC*C*C*0*0*0*C»C 

.5008250 

.5008245 

.5007203 

.5007224 

.5007029 

.5007015 

Flex¬ 

ure 

*c *0 0 *c *0 *0 

1 1 1 1 1 1 

1 1 1 1 1 1 

X X X X X X 

1 1 1 1 1 1 

CM CM CM CM CM CM CM 

1 1 1 1 II 1 

OiCiOiOiCiCiOiCiOiCiOiOi 

1 1 1 1 1 1 1 1 1 1 1 1 

OOOOOO 

1 1 1 1 1 1 

© 

Chro¬ 

nom¬ 

eter 

No. 

1841 

CM CM CM CM CM CM 
Ol Oi Cl 01 Ol Ol 

777777 

CM CM CM CM CM CM 
N N N N N N 
CM CM CM CM CM CM 

1 1 1 1 1 1 

CM PI CM CM CM CM 
CM CM CM CM CM PI 
CM PI CM PI CM CM 

1 II 1 1 1 

© to to tc to to to 

X X X X X X X 

»—< r-4 t-4 r- 4 »-4 »-4 r-H 

1 1 1 1 1 1 1 

OlOiOiOlOiOi*C*OtC*C»C*C 

777777777777 

Oi Ol Oi C> Oi O’- 

»-4 4-4 4-4 4»H 4-4 4-4 

1 1 1 1 1 1 

! * 

Chro¬ 

nom¬ 

eter 

No. 

1823 

CM CM CM CM CM CM 
01 Ol W W Cl Oi 

»-4 1—4 4-4 t—< »— < 4-4 

++++++ 

N N NNNN 
*0 *15 O »/5 *0 *0 

Oi Oi Oi Oi Oi Oi 

-T WTT W 

r4 4-4 »-H f—< »— t—4 

++++++ 

tc »C »C »C tc tc tc 
t>» n- p- t>- 

»-4 4-4 4-4 4-4 4-4 4-4 4H 
+++++++ 

Oi Ol Oi Oi Cl Ol *“4 •—t 4-4 4-4 4-4 4-4 

Tr'rrrr^rTf'rXXXXXX 

++++++777+7+ 

Ol Oi Oi Ol Ol Oi 
r-rpw vv 


»2 

p, 

la 

s 

8 

pd 

s 

© 


a 

© 


o 

o 


© 


o 

© 

a 

3 

•g 


C/3 © 
© 1-4 

jp 3 
pH to 


Tf CM CO CO X CM 

*—4 

I+++++ 


0 * 0 «Nhh 
+++1 + 


*c V N U-J r rr h.HOOV'if NN NMVr^tHfqiQCMNCMCMH MO^«*0»C 


I + + + + 4- +4- I 4-4-4*4- 


4" 4" 4" 4- 4- 4* 


E^£ 

© © 3 


ifllNHO-HM 
CO CO 


M»HMOrcCeo 

NNNtuOiO 


++I I + I I I I I 


I I I II 


t-HtHOOCCOC. otor WCOMC 

I I I I I I I I I 4-4-4- 


x x oi © oi x 
lilt!] 


© 

+- 

< 


X ci Ol Oi Oi X © © ^- © X *-• NOOiOOO OXXGlClOlCM CaCOClOiOOHOiCCO Oi d Ci w ci Oi 

4-4 4-4 r-t 4-4 4-4 »—< *—t •— r—< ^ f-H 4-4 

I I I I I I I I I I I I II I I I I I I I I I I I II I I I I I I I I I I I I I I II 


Chronom 
eter No. 

1841 

s. 

0.5008933 
.5008880 
.5007156 
.5007165 
.5006784 
.5006826 

Ci Oi © © © 
ictcaoccc 
uiiocr oi cc tc 
NNNNQCi 

gggggg 

tc *C tc tc tc »c 

.5008997 
.5009007 
.5007295 
.5007285 
.500C937 
.5006968 

.5005182 

.5005139 

.5005531 

.5005524 

.5007261 

.5007299 

.5007294 

.5008631 

.5008635 

.5008641 

.5008662 

.5008642 

.5008599 

.5006823 

.5006805 

.5006829 

.5006374 

.5006386 

.5006430 

cw©c-*c 

XCOCir.-CX 
*C *0 *C *0 X CM 
oc - 

C O O c O d 
OOOOOO 
*c tc *c *0 *0 »c 

Chronom¬ 
eter No. 
1823 

s. 

0.5008565 

.5008499 

.5006775 

.5006786 

.5006376 

.5006439 

.5007153 

.5007143 

.5007465 

.5007480 

.5009226 

.5009187 

1 

.5008623 

.5008652 

.5006911 

.5006921 

.5006577 

.5006578 

.5004857 

.5004879 

.5005206 

.5005206 

.5006966 

.5006948 

.5006986 

.5008294 

.5008297 

.5008282 

.5008309 

.5008302 

.5008275 

.5006509 

.5006502 

.5006460 

.5006068 

.5006072 

.5006050 

to X *C X —4 PI 
WCltOOC w© 

XXNNO© 

gggggs 

*c *0 *C tc *C **3 

Pres -1 

sure 

-»• X O O O O r-4 
^ N *Q © © © © 

6 

-T X 4-4 CM 4 *. CM 

©*o®©o© 

Oi O O Ci O O 
O O tc *0 to to 

X CM H Ol O CM CM 
*C © N *C © © © 

tOCMOMpjNXHHHHN 

©©©©to©©©©©©© 

O X O »-H OI Ci 

*0 »c 0 0 *c 


S 2 £ 

© © 3 


.CfO^COCN CM Oi O X Oi tD CNCMNOt UJ Oi *C N C*5 Ol QCCO f'JC VCONN Mf)H OOOOCMO 

X CM O t—< CM O NtCNtCMN Ci « h. C X C) CC <C *0 *0 rr © X Xt'-dOOiCOO—'XC mCMCO OinnMrtCS 


o r ^ o * o * q eg to to t©> cc © tD h- N X n X -*r -n* tt -rr -n* rr coct^ccocccic^rr tDh-r*t^r» 


X X C 
tDNNNNCO 


O 

*- 

CQ 

*3 

c 

H 


n 

□ 


P*< 


J*ONNNNN Nt^ONCOOi 


CM Ol N X Ci Oi NtOtONNOOX 

H fH H H ri H M f-t rH H iH ?-t 


OXOiNCNNOiOit^CN 


OiOlOOKSt' 


* OiX Oi OWN 


. 4f* 


ChNCCW 

OOOOOO 


OOHOiCH 
0 0 0 ^ 0*0 


©©©»-<© CM fhOhxWOOhMhhN 
f W o *0 *0 «i 00*00^5*0000000 


aoiHxoca 
rj’ rr o O O ^S* 


1 

a 

© 

04- 

C 03 

Chro¬ 
nome¬ 
ter No. 

1841 

•— © 

O w 

a 

© 

O 

Chro¬ 
nome¬ 
ter No. 
1823 


X O CC X CM CO 
xoxx©r>* 

«C C CM oi oi oi CO 
CTXr rrtcto 
CM CM x X X X 


& 


1-CNtOOW 
X X —i 1 -* o o 
XXXX CM CM 


X X XXO Oi 

NN vr tc*o 
CM CM X X X 


cm co cm co t x x 
X X O O "'T tt 
v wrcoxw 


COCMCMCMXTrCMXOiOcPPl 

rtCCTjHNCMOSOiONftM 

oocSoicii-Hccr>IcdcM-^oi 
c-.rixxxoicococooioix 
PI CM CM CM CM CM X X X X X X 


CM CO C o < 

Si 


B X CM CM —« X 
WMK'J'’* 
PI CM x X X X 


g 


CM O O X Cl 
o v N V to 

o c »o 4 *h 4 

O O X X t» i'" 
X X X X CM CM 


OWNhCO 
d x O to X X 
CM CM X X X X 


X tj* O O X Oi ^ X 
HOltCtCMCMX Ci 


to CM CP O Ci O X 
— X X o cc o 
o o ■*r x x x 


MtOCCOCNWCOOtCCi 
XXXOCCOOi'Tj’OCMO 

»-<i-JcM^-i-4rirrr^r>IcMPix 

ooooooxxx^^^ 

XXXXXXXXXTT*'«r'«f' 


*0*0 0100 X Ci 
O C -*r -rr »q o 
X X X X X X 


© 

4-> 

c 8 

ft 


O ■ • <-l 

2 °? : :2 . . 
o; Oi O O O «— 1—• 
Vh PI X X X X X 

tl tx tl ti tr, ti 
3 © © © z: 3 
<*<*<*<*<< 


°°..- 
P- X* X* oi Oi Oi 
-*-i 4-j -*-i 4-i 4-i -*-i 
p4 Pi P. P< ©4 Q| 
©©©©©© 
CCCOCOCBCOO} 


o o o o o o 


• • x 

CM • • CM 

C©tDNNN 
CM CJ CM CM CM CM 




4J *i 4J 4- 41 4i 

P. P. p. -- P. p4 
©©©©©© 
COOQOiCQCOCn 


4J +- 4P +-) -O 4J 41 

p p p p p p p 
©©©©©©© 
ujinuimwuxn 


• »X • • Oi. 

• • CM • • CM. 

Nir^i^xxoioioi^^-H* 

PI CM PJ CM PI CM CM CM ^ 


CM 

, - 

PI CM PI CM 


J V *j 41 4^ 41 -W 41 g ^ P 
©©©©©©©• O© 0©0 

oooocoooo^zz 


o © o 

cooc 


:OC 


• 5 ? p 
c .2 


ClPQQCQ OOCQOfi OOCfiOO CCfifiQOO QQfifiQOqcCfififi CfiflQRfi 


c 4. g 
d.’CS 


’tM'O'OtOtD 

<<<<,<< 


<0 to o o *<r *+ 


rf TT 10 *C to CO 
<<<<;<<; 


'OSJOiOftV 

<<<<<<< 


r'^rTr'rr*oo*0'Oipo 

«««««« 


rtTfOOtOtO 


h cm x o 0 hcmx^oco hnw^ioco •-* n m ^ o to n HciccnctONorwoHN hC'imvioc 


© 

> 

& 

03 

Jp 

c % 

45 ' 

s 

oS 

e> . 

I 

a 

44 

CO 


.s 

ft2 
OD g 
V 05 

■gm 

s. 

ssla 

. C> 1 J 

or-* 


£ 

out 

or 

4> • 

so 

a-2 

si 

oE 


o *« 
E q 

mW 


JsS 

•o® 

» © © .^ 


*! 

ll° 2 
& 05 >> . 

S C r 

a- ®q 
ZSCZ. 

6^ 

3 O Z® 
^OOO © 


£ 































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


153 


£§ 

■«* *H 

s?s 

N 1-4 

S8 

S8 

H 

«5g 

28 

oio 

S-H 

G O 

G-H 

G O 

®-n 

G O 

G -H 

G O 

g-H 

GO 

S-H 

OO'fOSNOO^OO^ < 
R«nn©«ion© < 
OGOOOOOOOOOOOCOOOO < 

D8f»COOOMNN 

rocococccoeococo 
xoooooooc oo oc oo 

^ ^ c ^ c o 
w w»r 8j« 

rrO—O'O—'^COCO 
»r © © © «r *r v »m o 
COCCCOCOCOCOCOCOCO 

C)-«»-t^NCG-G©8rX©-'CN*-Gf'G©M 

toxr*r»oi.' , ;u , :ccto»©«x^ i *fi©co^irir:tc^rcoc w ?Tj*co 

Q©H©GN 

cc iC 4C 

00 OC 00 00 00 CO 

GGGGGGGGG GGGGGGGG 
N N N N h» N N N N t"— N N r- N f-'. I *, h. 

GGGGGGGGG GGGGGGGG 

G G G G G G 

r- r- r- c- 
G G G G G G 

GGGGGGGGG 

GGGGGGGGG 

G G GGGGGGGGGGGGGGGGGGGGG 
r— c— i - — r— c— c— c— r— r— c— c— t'* i— r>» r— c— r— c— c— i— r— 

GGGGGGGGGGGGGGGGGGGGGGG 

G G G G G G 
N I — S N h> h* 
G G G G G G 

.5008952 
.5008937 
.5006860 
. 5006878 
.5007233 
.5007251 
.5007258 
. 5007228 
.6008988 

_ 

.5009076 
.5009064 
.5007318 
. .5007330 
. 5006966 
. 5006978 
. 5006968 
.5007324 

.5008057 

. 500.8059 

.5008418 

. 5008402 

.5010172 

. 5010166 

.500S227 

.5008212 

. 5008555 

. 5008557 

.5010316 

.5010327 

.5010327 

.5010322 

.5008550 

. 5007678 

. 5007674 

. 500.8064 

. 5008012 

.5009774 

.5009786 

.5009767 

.5009769 

. 5009789 

. 5008024 

.5008058 

.5008061 

. 5007681 

. 5007739 

. 5007674 

. 5007676 

.5008042 

. 500.8043 

.5009794 

. 5009824 

. 5009820 

. 5009803 

. 5009836 

. 5006908 

. 5006896 

. 5007277 

. 5007290 

.5009028 

.5009040 

.5008957 

.5008944 

.5006862 
.5006882 
. 5007235 
.5007247 
.5007252 
.5007224 
.5008977 

.5009079 
.5009071 
.5007312 
.5007321 
. 5006962 
. 5006970 
.5006970 
.5007333 

. 5008050 
. 5008063 
.5008412 
.5008403 

.5010188 

. 5010154 

N N if © O © © C N 
04 -1 © Cl N (N Cl X 

CN 04 © © X CCC©C?iO 

OC xx.xccccx 

OOOCGOOCO 

lOLQiOiCiXbiO^OiOtC 

,5007663 

. 5007667 

. 5008060 

. 5008042 

. 5009786 

. 5009790 

.5009776 

. 5009778 

. 5009793 

. 5008030 

.5008072 

. 5008052 

.5007673 

.5007734 

. .5007657 

.5007663 

.5008041 

.5008044 

. 5009799 

. 5009832 

. 5009825 

.5009809 

.5009845 

. 5006900 

.5006897 

. 5007278 

. 5007290 

. 5009035 

. 5009057 

.5008948 
.5008930 
. 5006858 
.5006875 
.5007231 
.5007255 
.5007265 
.5007233 
. 5008999 

.5009072 
.50090.57 
.5007324 
.5007340 
.5006971 
.5006987 
.5006965 
.5007316 

. 5008064 
. 5008055 
.5008425 
.5008402 
. 5010157 
.5010178 

.5008227 
.5008212 

.5008556 

.5008549 

.5010311 

.5010329 

.5010328 

.5010314 

.5008562 

. 5007693 

. 5007681 

.5008067 

. 5008043 

. 5009763 

.5009781 

.5009758 

. 5009760 

. 5009786 

.5008017 

.5008044 

.5008069 

.5007689 

.5007744 

.5007692 

. 5007689 

.5008044 

.5008042 

. 5009789 

.5009815 

.5009815 

. 5009797 

. 5009827 

. 5006916 

. 5006.895 

.5007276 

.5007289 

.5009021 

.5009034 

8f W Wfl'V’t V 
** —H —H *—1 i—H —H r« —H 1—< 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 

G G G G G G 

1 1 1 1 1 1 

»-H f—1 r-8 »—8 t—i —H 

1 1 1 I 1 1 1 1 1 

CDCCO«CCCCCCC«tCCCCCCDCOCCCCCCCCCCCCCOCDCCCO 

^ *“H *—t M —H «-* l—* *—1 •—< —* —r— >-8 1—4 r-4 —« —^ —S r~4 »—< *—1 M 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

00 00 OC 00 cc 00 

Mill! 

cococoeocococococo 

GGGGGGGGG 

+++++++++ 

V ^’f V NN NN 
©©©©•—•—••—'•—« 

++++++++ 

00 00 5 00 oc So 

+ + 4* + + + 

GGGGGGGGG 

+++++++++ 

CCCCCCCCCCCOCCNNNNNNNNN 
t'* t" c** c— i— i" r— r— c— I s — c— i« © © © © © © c © © 

++++++++++T++++++++++++ 

^ 4T rr 4J> -T 4J< 

© IQ »0 © © © 

++++++ 

G G G G G G G G G 

l©i©i©t©t©*©*©i©i© 

+++++++++ 

CtOCCOCCO 

IMI 

r-- r-r- r^. 

i i i i i i 

GOOCGOOCO 

—H — 1 4 r*4 f-< r-* —H «—I *—> H 

+++++++++ 

Nh>r^Nh.Nh»NNNNNNh*W«MMW«MWM 

occcccccccccocxxxxxxxxx 

+++++4+++++++++++++++++ 

v n- tj< rr 4ji 4j« 
N N N N N N 

+ + 4- + + ~r 

^OOO^GCO^CMCO 

—-4 •—< y—> 

vNO^NWhh 

hNvNXh 

HWNXWUJrt^CJ 


nX’TONH 

1 1 1 1 1 + 1 + 1 

+++1+11+ 

l l + l l + 

1+++11111 

1 111 + 1 1 1 1 1 1 1 1 1 1 ++11 +1 

+ + 1 +1 

WN^r ©uCOXNtj. 
w:»ON©XG©©N 
eoeccjNW^^^H 

+++++++++ 

G OG0CC5M0C<O 
NXtt©iO«N© 

1 1 1 1 1! 1 1 

©MC©G© 

©©XO-h 

i i 1777 

©N’TW©-©©© 

p-a^xox©©© 

1 1 1 1 1 1 1 1 1 

©p*a©Nv®<-'©XXW05GvGXG8r©00 
XC©a5--Nf-05©*Hh.«©NNXN-CCN 
-NhhNNNNNh^-h — -H — — ^4 

+++++++++++++++++++++++ 

cr^©ci©x 

NX® C©4j< 

++++++ 

GOGGGGOOOO© 

1 1 1 1 1 1 1 1 ) 

QC00GG©©GG 

1 1 1 I 1 1 1 1 

CO G G O G O 

—H 

1 1 1 1 1 1 

OGOOGNWXH 

1 1 1 1 1 i 1 1 1 

XOGXXXXXXGGGOOXOJXXOONON 

f—4 —-4 —1 r—4 rH 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

OOXHXO 

HH —H rH 

1 1 1 1 1 1 


oo»-400N-G'»?'C‘i^ri'- 

wMCrZMXM 

UOtO'^'tOGGCC'-l'- 

occccccccc~i^*croo 


G'^rocGGtcr-o 

T-HtCCN-CO 

e c M cc O', a C. « 
5 n- r- cc cc tc r- 

Iggggg 

> to i© O t© »© 


«05CCi(NCi 
iO C CO V 1C o 
O C r't (M !N 

a. x cr x c o 

G C C C — —• 


©ChiCCOOJNCW 
N CO ^ I' !>• C5 CJ CO 
« CO O C T - 1-0 LO N 
X. X X X. OOGGOO 

ooSgooooo 
1.0 uo iO «o c io **o *c >c 


-<L0 0Jt^(NC5XXC0CWNC'r^<C0'^MC0iCC0C50) 
COOJiCCCOM005COOCC5CiO>Oi.ONNCOXX CC -<r 
COCTNNW'rCOVXNh-'fiCCOCONNiOiOlOiOC 
t- t- J- G G O.OC-.NNNNNM-NN G G G G G 
GGGGGGCGCGGCGGGGCGGGCCG 
GGGCGGGGCGGOCCGGGGGGGGO 
iC iO iO >0 lO iO O iO iO C >0 i-O O *0 lO C >C O *C iC lO i-O O 


!>■ "i 05 X O ’T 
MOHO® CON 

ccccxx 

CCM'XX 
G G G C G O 
G G G G G O 
LO to U5 iO iO «5 


WHXV050C5NW 

MCQXCC5CMC5 
i.O iC ? iC 05 G C G N 
XXCCCNNNX 

g^ggggggg 

lOiftiOiOiCiOiCiOiC 


— GcO-'r-r — O 
— — CO-rCGO^ 
GGN-r-r-r^r-r'- 

gggggggg 

lOiOLOOiOiOiOiO 


lOrrCOCOC - C - *T v V X G X CO 
^pHioiococo w r« t' ic i-o ^ ‘O x 
xxxxco xxxxcgcc 22 

C C7 C O < C G © G ~ G 

-0 G G G <- 




'»0)N*HMC0C0C0C5OXr'05h'l0XCCC:01NWCC0 C0 05NWCCH 
NCNNNX>0vX'TC5N«NCC»CL0T-C*riC«O X O: X N 05 X 
o^x r"Tot , *’ri'f s xi-0’0 , T'*xxcc^CN r^G— 

n- r- o g g g g n- i - n- c- n* n- c- g g g g o © © r- r- c/: oo 

ggcg?gScgggSSSSgggggoco ccSccS 

iCiOiCiOiC»0‘OiOiC‘0‘OiOiO‘C»OtOiOLOiCiOiOiC>0 IOICIC«}IOUO 


©ON«^G©H4f 

G — , *roc*-'eC'*j-eo 
© © © © © © © © 

rr©C©NX 
© © © © I s * © 

©^N©XC©©» 

©©©©Nf'©©© 

NX® X©h©Gv©©XG©««MNN©©N4P 
C©CDCOC©CCCCCCCOC©COCOCOCO^C©C©CCCCCCOCDW5CD 

© ©N © © © 

NOh*»OX©NN'4r 

lOCNCMT-tCX 

c6©NOC(® 6 -4^6 

P4 M *H H 

GNX«©GN« 

©Nh©NN©© 

uo»xfccc6cctrctccD 

NCNNM© 
© © C © X N 

© © h» 

NG©©®NNOO 

h©hWX©--h 

OGGGGO *^—* 
w ^H^fH(NNNN 

©HCwCOV^XXGMNOf'-XHftftN’P 

©N®«®G©NXN®NNO®XGXGNv©W 

CCCCC5®®®®CCNXvOO----NNNX 

CM^rM©© 
O l’' C* © *r X 

©j ^ G CO CO CO 

XNNNNKlOtOO 


©c- cooct^o 

00NN©©«j<©©G 

©f'X©V©«'»PMCXP5t'N©X©©H05W©0 

NXOCtfO 

—H— 

—H —K ^4 —H rH —H —■H 

*-4 — 1 —4 —* —* <N 

hhhhhNhhh 

iHHi-l—IrHHi-HHHHHHHl-lHMfHHN'HHNN 


h««G-XOXO 

h©hNNNWN 

OG HCOGG 

COGCOCOCO4-400GCO 

XNGGXhhhO«h©GMhXh®OhGin© 

NN®vXh 

©©©4?'©'»r©)4riO 


©8r8r©8T8r 

© Tp © © © 8J1 ^ © 

^r»©^*'^’Tr>»©»©k©*©»©*©‘©^r‘0*©r?'i0^r»©uo^fi©»© 

»© i© ■v »C tO 


§8 


OCOWN NGN 
vNX vift V© 


i CO CO CO CO CO Ol 


OrrC©XVNN 

r^cc-n-GGO^t^ 

NN^N^ciNN 

t > »r > »*r-rGGG'*r 

WC'ICOCOCOCOCOCO 


OCOil-OONNCO C»ON© VM«05XC5«MO«XHX©©«XXX) OC CC rr i© CM ”> 
OC CO f-H r- CM G ©a —• t>- VXOX©CN , r©©©«C»r©©O^N««h*N i—« O © G © C 


G G N» G •© 
*—<*—• G G rr 
COCONNNN 


XC05X05XXXG 
05 C X y X X X X /. 
NXNNNNNNN 


r<HK-i,OiC!CCiOiOCl-iO-CCdfNlN-"-HO) 
WNNCCGC C N CJ N X X -r t N N -O C G G © 
COCOCOCOCMCMCNCMCMCOCOCOCOCOCOCCCOCOCMlMCMCMCM 


r- oc cm co cm 

N N 1.0 X X X 

co co co co cm cm 


oV©N©N©NN 
hOCNNXhNX 

CMCM^rOG©-**©-'?' 

a> G or x ‘O **o icuox 

CMf*C<6<WeOC©C©CCCM 


©NNO©N]TO 
©C5X©V vO)« 

•^r-roOGiCGGoo 
N h- X X X ‘ O 1-0 X 

cmcmcocococococo 


f'NMXNN 
O © G G -T T 
XXNNNN 


•»—4 • CM • *CO 

^ 'CM *CM • 'CM 

JJ i JL n ei c^> w co C| isr;?3SS^S3 
S — — — — —< — — — P)««NNnM« 


•'c5 


I 


cccqocca a 2225S55S 

0BOS83c3c3c3c3C3c3 C3C3C0C0C0C3C3C3 

*■* ^ »-s >-> >“i ►“> >-» >“9 


©N©CN©G©W 

C5C5XXXXXXX 

NNNNNNNNN 


oc c__ .. , _. . -, .. 

CO CO CM CM © © © rCNN-XNXX- _ . _ 

MXWXNNNNNMMMMXMMKWNNNNN 


* * J 

: i : 

co I I^r ! !© 1 1© Jn 1 1 • ! 
; : :<n ; In ; 1m !cq : : . : 

: : : 

: : : 

NI y i i 

led 

• • l . 

lc- 1 
• L . • 

I d cd co* co *r *r 4* »d »d r> r> i I 

. ■'T » 

• L • 

. »o I 
• 1 • 

j iopir) r* 


NNNNNNNNNNNNNNdXXX’J'^'TiO© 


p c a c c a 

c3 cS c3 rt c3 o3 


JD.O.O.C.C.C.C.C.© 


I— k. k. k. k. k. fc- k. k. 
®®®®®®®®®®®®®®®®®®®®®CJ« 


U b t. b U (H 

rt c3 C3 c3 c3 

ssaaaa 


CDOCCCQCO 

OfiCDCOQO 

OCQQCO 

OCDOQOOQO 

OeCQQOCCOCfiCQBfiCCfiOfifififi 

fiCQeae 


M.TrU5«5tC<OtOi® 

c© <© i© m 
<<<<<< 

?Cc©iO»0^r^r'^ , ^r»0 

<<<<<<<<< 

©©©©8pTPTP4r8r©©©©««©©©w*prp4j< 
<<<<<<<<<<<< <<<: <<:<<<:<<<; 

© © © © 
*<*<*<*<*<<1 

kC1«»«)OM105> 

hNCOV©©NX 

HN«8P©© 

*-‘C'lCO'8X'iOCOt>-CCG 

HNWi'©©NX®C^NW^©©NXGpHC}« 

h^hhhhiihhhNNNN 

HNCO^©® 


|M 

(Q . 

d 

5 s 1 

JG 

T3 

c-o 

JB 

< ti 

CB 

<5 • 

„ M 

£3 

so 

B 

■§„ 
kr. 'O 

«o 

15 

PS 

E* 


^ g 

ti 

>s 

S^- 

6> 

* 

€ a - 

P2 

si 

eta 

2 

No. 92. Fe* 
Fla., Ha 
King. 

H • 

P5 

si 

dW 

8q 

<2 

S3 

dW 

S5 

& ca 

Sdi 

daw 

a 



















































































Pendulum observations and reductions —Continued. 


154 


U. S. COAST AND GEODETIC STJBVEY SPECIAL PUBLICATION NO. 40. 


§ 

<© 

a 




© o 
© © 

S 3 o 

-T © 

So 

© o 

CM CM 
© © 

CM © 

So 
© © 

g§ 

C5 © 

© © 

00 © 

05 o 

05 © 

05© 

S-H 

SS-H 

6 -H 

05 "H 

fe-H 

S*n 



© © © © © © 


© © 05 © © 05 
in i-~ t- 
05 05 05 05 05 05 


r^C5WXC*5N 
05 X 05 00 05 00 
05 05 05 05 05 05 

00 OC 00 00 CO 00 
r- t- i- t— 

05 05 05 05 05 05 


©OMONiH 
05 05 C~. 05 CO 00 
NNNNNN 

05 05 05 05 05 C5 
t- 

05 05 05 05 05 05 


MOWNCO-<0-HTfO^WtO»0 
N X N N tc w N to O CO O 

lO *0 O lO *0 »C 1C lO lO o lO lO >o *o *o 

05 05 05 05 05 05 05 05 05 05 05 05 05 05 05 

r- r- i'- r~- t- r- 

O5O5O5O505O5O5O5O5O5O5G5O5O5O5 


05 05 05 C5 05 05 
05 05 05 05 05 05 


Mean 

s. 

0.5008027 

.50080-16 

.5009802 

.5009796 

.5007689 

.5007708 

.5008034 

.5008008 

.5008373 

.5008372 

.5010112 

.5010124 

.5009130 

.5009136 

.5009470 

.5009484 

.5011217 

.5011232 

.5008344 

.5008352 

. 5008704 

.5008698 

.5010464 

.5010481 

.5009732 

.5009715 

. 5007986 

. 5007990 

. 5007630 

.5007648 

.5007649 

.5007647 

. 5008010 

.5008014 

. 5009731 

. 5009762 

.5009757 

.5009750 

.5009754 

. 5007059 

.5007061 

.5007444 

.5007444 

.5009223 

.5009242 

Clironom- 

eter No. 

1841 

s. 

0.5008026 

.6008055 

. 5009795 

. 5009796 

.5007692 

. 5007708 

. 5008035 

. 5008010 

. 5008381 

.5008361 

. 6010104 

. 5010131 

.5009118 

. 5009133 

.5009155 

.5009484 

.5011218 

.5011228 

.5008345 

.5008351 

. 5008702 

.5008696 

. 5010465 

. 5010488 

.5009722 

.5009710 

.5007986 

.5007987 

.5007630 

.5007651 

.5007647 

. 5007651 

. 5008015 

. 5008020 

. 5009724 

. 5009772 

.5009758 

.5009762 

.5009751 

.5007052 

.5007070 

.5007442 

.5007439 

. 5009228 

. 5009244 


hronom- 
iter No. 
1823 

S. 

5008028 

5008037 

5009810 

5009797 

5007686 

5007709 

5008033 

5008006 

5008365 

5008383 

5010120 

5010118 

5009141 

5009138 

5009485 

5009483 

5011216 

5011236 

5008343 

5008354 

5008707 

5008699 

5010464 

5010474 

5009741 

5009720 

5007987 

5007993 

5007630 

5007645 

5007652 

5007643 

5008005 

5008009 

5009738 

5009752 

5009756 

5009738 

5009757 

5007066 

5007052 

5007446 

5007448 

5009218 

5009240 


o " 

© 






Flex¬ 

ure 

P-4 p-H p-H 1—p f* 
♦—I p^ »-H p—< rH 

1 1 1 1 1 1 

o o o o o © 

1 1 1 1 1 1 

© CO 00 © 00 © 

1 1 1 1 1 1 

00 00 CO 00 00 00 

1 1 1 1 1 1 

©©©©©©©©©©©©©©© 

1 1 I 1 I II 1 1 1 1 1 1 1 1 

hhhhhh 

rH »-H i“H f-H rH pH 

1 1 1 1 1 1 

<D 

«5 

Chro¬ 

nom¬ 

eter 

No. 

1841 

© © © © © © 
CM CM CM CM CM CM 

++++++ 

ooooxoooooo 

+„ + + + 

© © ©© © © 
CM CM CM CM CM CM 

++++++ 

© © © © © © 
© © © © © © 

++++++ 

coocooxooooooooooc»oooo«oo© 

Hji Tr N* rr -T XT XP ”'5' TT 1 TT TT TT TT 

irppsf wr?* 
©©©©©© 

++++++ 

« 

Chro¬ 

nom¬ 

eter 

No. 

1823 

00 00 OC 00 00 00 
CO CO CO CO CO eo 

CM CM CM CM CM CM 
CM CM CM CM CM CM 

++++++ 

© © © © © © 

1 1 1 1 1 1 

TT rr nr —< T** 

CM CM CM CM CM CM 

++++++ 

1 1 ! 1 1 1 1 1 1 1 1 1 1 1 1 

© © © © © © 

++++++ 

Pres¬ 

sure 

CM CM © rH rH © 

CM CM CO © © © 

CO © CM pf © CO 

•pr CM fp. CM CM CO 

CM CM rH rH rH CO © pH © © Tf CM CM © 

00 CO rH © ry 

1 ++ 1 1 + 

++++ + 

+ + 1 + + 

1 +1 1 1 + 

++ 1 + 1 +++++ ++++ 

++++++ 

Tem¬ 

pera¬ 

ture 

© OO © © 

■sr 

1 1 1 1 1 1 

© -r © OJ 00 CM 
Cl CM «—i CM CM CM 

777777 

© © CM © © rH 

00 GO 00 00 © 

1 1 1 1 1 1 

© © © © 00 rH 

© © oo 

++++++ 

©rHpH©CMr^.rH”*FCOr^CO©©©© 

©r^©©©i^h-©p-t^i'-cooooo© 

777777777777777 

p- © © © CO t'r 

2S282S8 

1 1 1 1 1 1 


$ 

■H 

i 


’O 

o 


! u> 


© 

o 

C9 

P- 

I 

o 

© 

X3 

•d 

45 

c 

g 


c 

o 


o 

o 


o 

t- 

C 


§ 

I 

V- 

© 

Pm 


So' 


.-ie<l000>0 0r-<C»00.-< KJOOOOOH 05030000 O —I O O O O O O 05 03 o o o o o ooooooooooo 


I I I I I I I I I I I III 


I I I I I I I I I I I I I I I I I I I I I I I I I I I I 


e>t-«N«N 

OCUOO rrN 
05 05 t'* t'- © © 
• NNOCJNN 

o o o c © © o 
O o o O © O 

iO lO LO iO 1-0 iO 


05 © -*r co -r •—• 
© co © oc co © 

COW«^H 
OC OC 00 CO C O 

© © © © © o 
ic lo lO o lO »o 


C to ic M H UJ 
05 O CO O C »H 

r-. -H to to CO CO 

§ 05 C5 05 ph •—« 
© O O —< *h 

o o o o o 
to »C *C lO to to 


C O N N N H 
»H^CCr'-rh. 
W (N lO to CO CO 

00 00 00 00 o o 

© © © o — —« 

C O © © © Q 

to to to to to to 


ONO’T’tt^tOOQOCOOOON 
© to to »0 05 05 00 l''- © CO CO rH o 
COOO^-HNNNN'-|-'QOC5C5 
0505CC«Nt>.NNOOCOCJ5C5CJ 

©©©©©©©©©©©- 

OOOOOOOOOOO 
lO O ‘O to to tO to »0 *0 ‘O to 


05 05 
. 05 05 

) o o 

5 O O 
5 to tO 


ONH-rMN 
CO*?MONN 
*—« r-« to to CO CO 
N N N N O O 

gggggg 

to tO to *o to to 


C 

°z (S 

§ >roo 

pH 4-» ^ 

g© 


05 I s - © rH —T 1 >H 

to O t N tO 

OOOOOONb* 

• co oc 05 05 
9 o o o o o © 
o o o © o © 
to to to to to to 


iONNO*tCC 
HHmoiNN 
00 00 00 CO o o 

gg £ goo 

to to to to to to 


CO 05 H- -h 00 05 
<T N 03 05 N O 
CM CM © © CO CO 
05 05 05 05 pH H 

8 ©©©rH — 

© © © © O 
to »o tO to to tO 


tj< © 00 © CM CO ^"NCOinOOiOCOCONNrrOOOCD 
--r w h /. 05 rr CM —I IN LO IC to CO -1’— © N to © 

CM CM © © CO CO ©©CMCMCOOOOOOOCMCM©©©©© 
OOOOOOOOOO ©©COOOt'-t'-tHt-OOOO©©©©© 

ggggss ggggggggggggggg 

to to to to to to to to to «0 to ‘O *0 to to to to to to to to 


to -r O 00 00 CO 
to O to CO 00 

CM CM CO CO CO -cr 
t- 05 05 

gggggg 

to >o to to to tO 


CO © 

© H 

t- 

Ph OT 



Tem¬ 

pera¬ 

ture 

. 00 CM CM CO CM 30 
© ri © H- CO t>« 

CD © © © © © 

»H PH p-H pH rH pH 

00 © -r 00 © © 
© © r» © © © 

p>I r~l oo oc r-1 

pH rH pH pH pH pH 

CM CO © CO © t-r 

© © © © © rH 

r>I © © 

pH pH rH pH pH pH 

CM © © pH © O 
I^M3;hhcO 

CM CM CM CO CO CO 

■*r00©t^©'<j'COCMCO-r-*r©©C0© 
C O © O © CM O ©PH CM PH CM CO XT © 

©©©©©©©oc© ©©©©©© 

© © to cm © 

© •© 00 © »H © 

C 7 00 © © © © 

pH h pH rH rH rH 

O 

a 

r—t 

Final 

mm. 

1.9 

2.1 

1.9 

1.8 

1.6 

2.0 

h-aNDXO 

H rH ph —4 p-h CM 

© © 00 © 00 © 

pH CM rH CM P-H CM 

00 00 © © © f'p 

t-©r>-r-oooooot-r^oooooo©©co 

HT to © © oo © 

rH ph rH pH rH pH 

53 


-4 CM © © rH CM PH 

© CM © ph CM CO 

00 © © PH © CO 

© 00 © CO © © 

©MWpfOCOHHHHXNMOCi 

© 00© o© © 

H 

a -S 

t-H 

g © © © © © © 
S 

HJP © © © © © 

TT © TT © © © 

© © tt 

©©©©^©©©©©rr'tj*©©^ 

© -r tt © © -h 


OpH 

ff 03 
© > 
•H *H 
© 
© -H 

a 

o 


A A®*"* 

rQ O 

O 

4H 


•o "tf CO CO © 0- CO 
pH lO to CM CM 
CO CO CM CM CO CO 


O X 00 N © 

•H H © © H* TT 

CO CO CM CM CM CM 


CM CM CM —< —• —^ 

r- co co cm cm 

CM CM- 


to to rH h CM H 

--... © O 05 05 -t t r 

CM CM CM CM CO CO CM Cl CM CM 


r---ls.N— -h^hCMOOCOCMCMCMN 
© © © © CM CM CM CM O © © © © *0 »0 
CICMCOCOCOCOCOCOCOCOCMCMCMCMCM 


CO CM © "tr © C 

© © © <-h o6 

H* © CO CO CO CO 
CO CO CO CO CM CM 


A A o» 
<5> BSH 


^ O O’t V *T CM 
p-H rH lO to CM CM 
CO CO CM CM CO CO 


oo >o t hi 

© © © © H* rt» 
CO CO CM CM CM CM 


S © © CM § 
CM CM CM CM CM CM 


COXCOlHM 
O OC5C5 ’7 f 
CO CO CM CM CM CM 


©CO 00 ^r©t'Hr^© 00 i'- 06 c 0 CMtO© 

p-H CM ■**" -T 00 00 00 O^'tHrHHfHO 
•otooo-HpHfHpHOOintomioto 
CM CM CO CO CO CO CO CO CO CO CM CM CM CM Cl 


»-h tO CM 00 00 C 

LO N N N C tO 
■'T -PT CM CM © © 
CO CO CO CO CM CM 


© 

4 -* 

o 


: IS : : 

Zh rl 00 00 ot 05 ©5 
© CM CM CM CM CM CM 

h h C H M H 

OT 03 cd 03 c3 C3 


VO • •© • • 

Hr to to © © 
Im h tl ki Ih 

<<<<<< 


-h • • CM . • 

u C m >4 u u 

ChP,Q.Q4Q,^ 

< < <<i< < 


© • <N I • 
H • 'H • • 

5b S S i 
< <! ■< <! < < 


:S3 


:a 

i 


• 50 
•IN 

2 *o 3 


^ 5. I. I. 5. I. h h 5. 5. 1. 5. 5. 5. L. 

p.o.p.c.B.p.B.p<p.ap.p,aao. 


^5 ^5 ^5 

cJ c3 c3 o3 cC c5 


si 

CL" 


QQQOQQ OfiOOQO fiQOPfiQ OOPfififi CPOQOftOOQOQOCPOOQ fififiCPQO 


to © tr tt © © 


© © to © -rr 
< *< < < <5 <1 


© © ‘O © rr 'T 


© © © © nr rf< 


rr-<r©©coo©©©tO’t < Tf'r'j' 


© © © © -V -V 


to 

I & 

CO 


»H CM CO ^ © © CM CO rr © © *-H C"l CO ’’J’ © © i-tCMCO-^tO© *-<CMCO^r©©t^0005©^HCMCO»r© i-H CM CO ■*»* © © 



§ a , 

0J- 

t>>S 
3 £ 

O S3 

W 

§'<> 

5? 


■8 S 

o C 

g| 

Wti 


2§ 

0) 

o^ 

55 



















































































5007690 | .5007692 , .5007691 i 979.554 


INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


US «•* 

88 

m 

CO 

kO 

os c5 

0 0 

0 

fe-H 

00 _M 

OJ 71 

00 

CS 


-H 


ss 

Os Tl 


—4 CM 

*3§ 

& © 
CC ii 
OS n 


SOO)OONO»CN »» iO O 'O CO 

OOtOT’T’TTT CO CO CO CO CO W Cn C4 M N M 

0i0«0>0i0*0»0»0 CS OS OS OS Os OS »—I r—i r—i r— • t—< 

3SOSOSOSOSOSOSOS Os Os Os Os CS OS OOCOOO 

i- r- i>- 1 >- 1 '- i'- t- oo oc oc co co oc 

3iC5C3GvlQOQ O O O O O 05 Q 05 C 1 05 05 05 


■ONCOCiC 

:cccoccio 

5 tT. id »C kO ‘O 


r-oocor>-eooo<’co 

M3505C5'H-->0 0 

co>6t-oocoooo 

I^NNC5C5C5CiCO 

88888588 

o o >C O iO iO lO *o 


oo oo —< oo co -r 

—i CO - O —< 
NNOOCOCO 
CO CC h- CC 00 

888888 

to »o *o to to o 


CO 00 00 CD © —i 
CO CO 00 00 Cl CO 
CM CM to t-O CO CO 

§ CO SO CO CC 00 

88888 

Id *o O lO IO o 


(O lO H (O C5 o o 

I- l - MNOt 1- 
Cd Cd C*. CC CD C^- CM 
CC 00 0C CO CC CO CO 

8888888 

tC »0 40 40 to *o *o 


C5-NCCCOCNC41C 


tC »0 CCCCCOCOCOCOCCCOCO 

ooococooo 
ooococccocccooocoo 

O5O5O5O505C5O5C5O5 


iC t" W a; O M N a cr. coco 
cctc<'cd<*<occ<*-r<-i.o<i 
(NCMW(N(NOlC^(N(N(N(N(N 


»C CC M CS 0C 05 <N CV I- CO <« 

£0 CO CO CO CM Ol »— 1 — < <■ CM CM 

oc o£ cc co co cc ».d io to »r. I- I- 

888888 888888 

id c ic »d id »o idididtdtdid 


cc i - co — cd oc <_ _ 

aciKccc'Ccco 

W Id id Id 1^ N N t' 

888888888 

id»didid>d;idididid 


DOC ©to CO CO 00 00 — COCO 
S <• c_ t'- <" CT. CM CO •— CO 

s os cr- c* -- 


or c 

. .. 

OC OS OS CT- Cl CM CM CM o Q O C 
lO»C4C>OCOCOCOcOOC5dOCG^ 

S r CCCCOCCCQO 

©cccoceo©©© 

ididid'didioidididididid 


^MrHNCOlOCCCO 

oimoooHHor 
coascsc-ccoococ 
t» r-- 

88L_ 

»d »d »d O »d id id ‘ 


05 N O O N CO 

— i—I O r- ' 

NNOOX" 

COCONNCC 


t'- cs co t — co 

CM CO CO OC CO CO 
CM CM tO 40 CO CO 
_ _ - - - CO CO CO CC OC OC 

oBSSco 8O8SC 8 

Ld id *o id id o id id id >d id »d 


OC CC CM c cc t'- 
CO C*. CO CO CO CM CM 

oc or or co co co co 

cccccco 
C Q Q CO c o o 
id >d >o >d td id *o 


— CM 05 CO 05 1-4 CC CC uo CO oc 

iC CO CM C-5 t" O - - - • 

CO CO CO CO 04 CO 
CC cc CO CO CO CO 

888888 

Id Id Id'd id ‘d 


cc oc to co oo <• vN^rCr-^iotciN 

CM CM CO << 1C OC CO — CM OC CC l- o 

r- -- o o di d) aacrcrcrccc-H 


id id id id i' n 

888888 

to to ud »o to 40 


888888888 

ididididididididid 


»HO!^C'4-Ot^VMOO 

OC«idCNCOOCCM(N-’f 

oc csa acMiNcociccoo 
id Id Id *d CO CC 'O c oc « X w 

888888888888 

idid»d*didid'Oididididid 


.5007690 
.5007663 
.5008001 
.5008011 
.5009797 
.5009810 
.5009821 
. 5009801 
.5008067 

.5006717 
. 5006720 
.5007062 
.5007051 
. 5008804 
. 5008815 

.5006246 
. 5006236 
.5006591 
.5006588 
.5008309 
.5008329 

O ID CM rr OS OS cs 

I- X 1- CM c »d CO 

CC CO Cd CC CC CM CM 

y. x x c 0 c 0 
§008880 

id Id Id Id Id Id 0 

00 OC to -« 1 -* Tt* 

10 cc *-H CM CO cs 

CC Cd w CO CM 64 

OC 00 CO cc co -•£> 

888888 

idididididid 

^niOkOCN 
CM Cd t" I - Cd 

' -rr -^r 04 CM 
id id *d id t' n 

888888 
id id to id id id 

N^OC 0104y C04rf 

Of^cd—••n- 1 -asi-cc 
oscsrdcdo. ccco 

Tf idldldl-NI-h- 

ccocccc 80 

id »d id id td id id id »d 

.5005889 

. 5005905 

. 5005936 

. 5005952 

.5006278 

.5006261 

. 5006293 

.5006269 

.5008032 

.5008039 

.5008023 

.5008032 

1 1 I 1 1 1 II 1 

CM CM CM CM CM CM 

r-< *—< r-H rH r —1 M 

1 1 1 1 1 1 

co to CO CO CO CO 

1 1 1 1 1 1 

CM CM CM CM 04 OS CM 

1 1 1 II 1 1 

04 CM CM CM CM CM 

1 1 1 II 1 

04 04 CM CM CM CM 

1 1 1 1 1 1 

222222222 

1 1 1 1 1 1 1 1 1 

CMCMCMCMCMCMCMCMCMCMCMCM 

nHHHHHHHHHHH 

1 1 1 1 1 1 1 1 1 1 1 1 

MCMCMCMCMCMCMCMCM 

CMCMCMCMCMCMCMCMCM 

+++7+++?+ 

CM CM CM T 

*-• r-H r-l O O O 

++++++ 

CO CO CO CO CO CO 
Os OS Os cs OS Os 

++++++ 

OC 00 00 OC 00 or 00 
O O O C O O O 

777+777 

CM CM CM CM CM CM 
CdCdCCfdCdCd 

777777 

■*fr -n- -n* ■*r -n- 
id td id »d id 10 

++++++ 

ccooor«^TrTrrr-»f-rfi 

ocoooci'-r^o-i^t^^ 

+++++++++ 

^TjiCMCMrrCMCMCMCMCMCMCM 

osc^cscscscscscscs 

1 1 1 1 1 1 1 1 1 


00 00 00 00 00 CO 

1 1 1 1 ] 1 

2 T 2 2 2 

+++++++ 

00 OC 00 OS os CS 
^ »—• *- CC OJ CO 

++++++ 

ococ-.oo 

II 1 1 1 1 

t^-r^r^cocococococo 

kOtOCOCOkOCOCOCDcOCOCOCO 

CM CM *—< CM i-h *—» 1 —< •—< »—4 

1 1 1 1 1 1 1 1 1 1 1 1 

rjoococooocooco 

CM rf 1-4 eo 00 00 

id d* Id O 0 V 

—H 

10 U0 t"* O IO CO 

CM to CM 1-4 CO CO 

00 00 CO co 00 

csr-coscor^cocsto 

r—i 

t^kOCMCMCMt^—4i-4t-i-4CSCM 

+++++++++ 

++ 1 +++ 

++ 1 +++ 

+++ +++ 

++ 1++1 

++++++ 

+++++++++ 

++ 1 ++++ 1+++1 

t^e^CMr^csioeokCCM 

J^22222225m 

7777T777 i 

xoHidcoH 
CM CM C? CM Sm CM 

1 1 1 1 1 1 

rr X O id r- Oi 
CO Ud 1 - 00 00 CO 
CM CM CM CM CM CM 

1 II I 1 1 

»o eo to *— oc os 

N 4^ OC os 00 

CM CM CM CM CM CM CM 

1 II 1 1 1 1 

CM CM CO CC CC 

r- i- 1 - 1 - 1 - 

Cd CO CO CO CO CO 

1 1 1 1 1 1 

00 OS CO CM to 

C. CM CM CM — O 

777777 

OSCOO-CMCMtOi-iCdikO 

kCcdJTftOTt'rr'iOXSiO 

777777777 

o>y.w-'ONooid--4ccoo 
C©H 1 1 — 11 .—<o «—<—1 0 0 *—1 «—1 

^-4 *—• r—i r—i t —4 —4 —4 r—i H 

1 1 1 1 1 1 1 1 1 1 1 1 

ooasooooos—«csooo 

1 1 1 1 1 1 1 1 1 

hh° 2 E 2 

Mill! 

CsO-hOCJh 

Mini 

O CM CM O CS *—• CS 
i-ihHh 

1 1 1 1 1 1 1 

2 2 0 2 2 00 

1 II 1 1 1 

oo 0 2 2 2 

1 1 1 1 1 1 

OSOShCSCSChOJh 
»—4 *—4 *—4 

1 1 1 1 1 1 1 1 1 

CSOOOOOOOHNOO 

»—4 r4 H —^ rH 

1 1 1 1 1 1 1 1 1 1 1 1 

.5007766 
.5007747 
.5008068 
.5008039 
.5009863 
. 5009895 
.5009902 
. 5009898 
. 5008181 

. 5006906 
.5006894 
. 5007251 
.5007236 
. 5008998 
.5008994 

.5006418 
.5006423 
.5006804 
.5006791 
.5008543 
.5008552 

.5008565 
.5008549 
.5008554 
.5006824 
.5006794 
.5006467 
.5006467 

.5008612 
.5008620 
.500P896 
.5006888 
.5006542 
. 5006566 

CCNCCb-OOS 
04 — cc ud — 0 
CM 04 4.0 iO Cd CO 
Id Id Id Id I- N 

888888 
Id Id Id »d *d Id 

.5005038 
.5005047 
. 500.5407 
.5005401 
.5005405 

.5007169 

.5007180 

.5007178 

.500', 202 

.5005968 

.5005982 

.5006072 

.5006074 

.5006359 

. 5006328 

.5006415 

. 5006400 

.5008117 

.5008123 

.5008108 

.5008150 


oc 

XOON^Scof 
1-NXX05C01 

S 88 S 8000 C 

OOOOOOOOi- 


00 H N Id Tf o 
CO O >0 CM I- OC 
OOMCOCO 


CO CM rH C5 CM 
lO to 05 OC CO CO 
— 'O CC CO cc co 
• —; O r~ ^ 
! C 


W J N—' '-'J ' ' 

<• co *-o ■ cc cc *0 

CO CO CO 05 CC id id 
cc or a co co co co 


Id Id Id Id Id Id Id Id Id Id Id id Id *d !d »d Id Id 


CO Tf- 05; O. ‘O 

1 ^. o; cs co co 
00 OC co CO co 

888888 
id id id *d id id 


O 05 CO CM C I'* 
Ol CM CO CC CO CO 
id id id »d t' S 

888888 
id id id id id *d 


-^ — <• rfCMCMCMCM 
id Id Id Id. L* N N N 

888888888 
id id »d »d id id *d id »d 


cooc^rco^-r: 


CC5CO0OOOC5OOO 
Id id Id Id Id Id Id id'd Id id Id 



CMCOOOCO»-4COCICICOCO 
CO 10 Id Id CO Id Id Id Id 

CM O CO 1-4 CO CO 
CO CO CO CO to to 

CSNOf CO 
id id I'* td CD ‘-D 

cs cs cs 00 

to 10 to co to to to 

CO O CO CM 00 

CO CO CO CO CO CO 

CO to 00 CO CO 

to »o to to to to 

Ud»'-CC<'00t^00^C> 

tdidotdididididid 

r-OO^OlCMCOCOtpsOCO'^'^ 
Id lO C C CO Id O O lO 'D Id D 

CMt^TCSCO—---COGS 
CMOOCOCSOrrcOcOCM 

rpCOONOCO 
C *r N »d »d v 

cs 10 10 O CO O 

CM 1—1 co c© r— cs 

CM CO 1- O Cl O 

to to to C- CO 1-4 CS 

00 00 00 00 cm 

00 OC CS os cs cs 

C cs 0 0 to 1-4 
Cd C C Cl CC t-O 

C500-— COOOCSv—CSO 
l'»^-tOCOCd< , COOCt>- 

OSCOCSCOCMtOCNiOOeOCMCO 
tdCOCCOOidXN^f !dO« 

osooosoooscsoJoso 

©Hl^®-4 —M r-4 r—i r- 4—4 CM 

CM CM CM CM CM CM 

CM CM CM CM CM CM 

HHHHHC4H 

CM CM CM CM CM CM CM 

CO CO CO co co CO 
CM CM CM CM CM CM 

oo 00 oc r- r- 


•—4 t—i f— r—i r—i r—i r—i r—i —4 1 —4 r-* ^ 

©OOCOidOOOCOOid 

05 05 COO 05 N 

00 cs as 00 os 

t- CS CO CS 00 CS 00 

CS CS 00 00 CS CO 

00C5O0S05CS 

ooooosooooososocos 

eocoooooot^oor-oooooo 


hhhNhh 

^ ^ ^ ^1 H 

HrtNiHHHH 

HHHHHH 

hhNhhh 

„_«_« 

Hi*4 *-*CMi-4Mi—IHCMi—IHH 

05 ^4 ^ 0 CO l-l 1-4 0 

•*r t Cs 0 O CM 

00 0 rr cs os CM 

CM iO O O CM O 

CM CM 00 CM 0 as 

00 os 0 00 —< 0 

C.OOCOOOCSCM1-4CO 

CM^1CMOCM*-4CMO^COOOCO 

^idirjidoidididid 

to 10 + 10 to lO 

+ to 10 + + to 

»o td to to tb to to 

id id tji id id mi 

■^1 to ^ to to 

Tf 4JUO Id to 4ji 1 C Id Id 

tOtOtOtOtOiOtOtOtOtO^tO 

iHP'OOOOO-rOOOOCO 

-rNWrOS-HOiOO 

00 -r O CM ^ OO 
vhCOOMv 

1-4 00 CO CO CM CM 
O W C5 CO f-4 00 

00 CM 00 co oc 0 

00 cs c- oc — O 

o^-^i-rcof^ 
OC to O CO CM 

O 00 CM to CM 

CM CC cs to to 

CO CM CM CO OO O O O CM 
COOOOOrJiOSCMl^OOCO 

<*oo<’CMtocMOcsasooeoto 

<«C^CM—cOCOCMO<*CMOOCM 

NCOOrHWCONCOO 
CM CM ‘ ''d * C »Q I d 0 

CO CO CO CO CM CM CM CM CO 

CM CO to CO CC 00 
CO©^^l'N 
CO CO CO CO CM CM 

O cs 06 co cm 
cr.' 00 <0 O' c. cs 

CO CO CO CO CM CM 

CM CM CM CO OC 1^ 
cs cs CS CO CO CSC 00 
CM CM CM CO CO CO CO 

O C CO CO CM 1—4 

cs OS CO CO 00 00 
CM CM CO CO CO CO 

05 cs CS C CM CM 

i'- r- •*}* to r»4 

tT Tf TJ* CO CO 

COtOCMCOCMCSOOOCr^ 

cscscorcco<'< , <4'<4 

<*rj*<’TrTj4cocococo 

osoooicMcotoo^oooooct^ 

HHHHCicsosaoooo 

<4<4<1<1COCOCOCOCOCOCOCO 

tOOOQOOCD-HCMtO-r 

H OS O CO CD © td CS CM 

NOONOrr 
CM CO CO COO C50 

cm 00 »o 00 *0 
00 cs cm 0 mo 

00 00 CM to CO 1-4 00 
id O lO H CO CO 

CO CM 1^- CM CO i—l 

1 - to 00 *-• ro 

O CM CO 00 O 
OS — CS to 

COXO-rr COCDM 
COtOCO^C.'CSOtOO 

CMOOOCtOCOOOOOt'-<4CO 

COHHXiHCMiHXr*i-4XO 

NOOididOOdoin 

HHOOiOiC^tO 

COCOCOCOCMCMCMCMCO 

NNOiHCDid 
kO»d)*7--i-t- 
CO CO CO CO CM CM 

CM CO CM CO O cs 
00 00 co CO cs 00 
CO CO CO CO CM CM 

CS CS CS CM CO 1-4 *-i 
00 00 OC CO CO OC 00 
CM CM CM CO CO CO CO 

CO CO t'- 00 f— 0 

00 00 »o to r>* 

CM CM CO CO CO CO 

CM CM CO to CS CS 
I- n *t *r ^ 

-r rj* <TJ1 TJ1 CO CO 

NC5tdNididididid 

XXtdldid'f-3 , *fT}i 

Tt*-*flTj1TfTt<COCOCOCO 

<4<4i-iOCSi— oocscccococp 
»—ii-4<-4f— ioOCsCOCOOOOO 
<1<1<4<1COCOCOCOCOCOCOCO 

May 17-18... 

May 18. 

Mav 18. 

May 18-19... 

May 19. 

Mav 19. 

May 19-20... 

May 20. 

May 20. 

May 26-27... 

May 27. 

May 27. 

May 27-28... 

Mav 28. 

May 28. 

June 8-9_ 

June 9. 

June 9. 

June 9-10_ 

June 10. 

June 10. 

June 16. 

June 16. 

June 16-17.. 

June 15. 

June 15-16.. 
June 14-15.. 
June 15. 

June 27-28.. 

June 28. 

June 28. 

June 28-29.. 

June 29. 

June 29. 

July 12-13... 

July 13. 

July 13. 

July 13-14... 

July 14. 

July 14. 

July 20-21... 

July 21. 

July 21. 

July 21-22... 

July 23. 

July 22. 

July 22. 

July 22-23... 
July 23. 

Julv 27-28... 

July 28. 

July 31. 

July 31. 

July 28. 

July 28-29... 

July 30. 

July 30-31... 

July 29. 

July 29. 

July 29-30... 
July 30. 

QQQfiPOfiOQ 

QflOOOO 

RfifiOOfl 

ORROROQ 

ROPRflR 

POCQCQ 

fiCOPRBORQ 

RPPPPPPPPPPP 

cOcC*0‘0'»r'-rTr^riO 

CO O id id rr n 1 
<<*<«<<<*< 

C CD >0'd T i? 1 

Tf Tj* Tf tO »C CO CO 
<<<<<<«! 

^i to »o co co 
<<<<<< 

co CO to to ^ Tt4 
<<J<J<<J<J 

COcOtO»OtO<4-t4'»f‘-?< 

<<<<<<<<< 

CDcOCDcOtOtOtOtO<'<4< , <* 

<<<<<<<<<<<< 

^CMcoTiocor^ocoj 

*-i CM CO 'IT t/5 CO 

Y-4 CM CO rr to CC 

to CO CO *H CM 

v-i CM CO to CO 

»-4 CM CO ^ to CO 

v-4CMCO<4CStOCOl^OO 

*-*CMi-4CMco<iosoioor»ao 

H H rH 



• 

8J 
^ • 

©E* 

S5 


8* 

© 

•a.- 

of- 1 

s> : 

6$ I 

>5 


& 

Js-i 

r® j 

A a 

► .■StJ 

.’ge< 


ft 8 -r 

ft 8 ® 

■*-> 

Sri 

O 8 
b‘t»§ 

C c O • 

L 0 s 
a-a§ 

O qO 

CO . 

■&<* t»>® 

ft® ►> 

to^ 

0 - 

c ® a 

— (A r' L-i 

o« ® 
•a a f 


d&- 

Sc 


2 q co 
2 O »>• 
«UcaS£ 

£ 


£ 


O D 
UOO 


CS 


^ © 
0 c 

— kl 

■*» 03 

££. 

2.g 


c n © 

s a 
m t- 

|5 

00 a 

S.2 

dS 

Z, 


■a 8 


•o . 

BQEh 


SC 























































































Pendulum observations and reductions —Continued, 



156 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


53 




88 

gg 

hp CM 

CM © 

X 0 

© i-H 

X © 

HP O 

ii 

Is 

0 © 

X 11 
© M 

15 

S3 

05 HI 

CO 

X 11 
© 1* 

05 © 

is 


o •• 


©»—©XCM©©©© 

^M(NCS(N(N(NC^WC^ 

^.O dddddddd 

Q X X X X X X XXX 

©©©©©©©©© 


*- ^ a. o o o 

hGCM'I' 

cdcodo 

X X X X X X 
05 05 05 05 05 05 


NOOhNCHO 
PJ M N M - 
X X X X X X 

o o o o o o 

X X X X X X 
05 05 05 05 05 05 


Hp X X X X X 

Hp -p Tp Tp -p Hp 

© d d © © d 

X X X X X X 
05 05 05 05 05 05 


WNOOCOO 
aXNXOCN 
u; iO lO >o 1C 

© 05 05 05 05 05 
05 05 05 05 05 05 


C«P5«»00 

x x 8 x 2 3 

05 © 05 05 05 05 
t>. N I - U I '* 

05 05 05 05 © © 


c c 

50 t 


gg? 

hj. © t 


ViCfl-XOtOCCUO 
»-«Wr-OC(NCJ-(N 
OOMNCICCOO 

• ©©;£©© X x : 

*ggggggg= 


to t 

d 


i to to to to to to 1 


O CM rr O © X 
lOOW-CN 
L- I- — — XX 
hp hp to © © © 

gggggg 

to to to to *o »o 


M O 'f C h M 
Hp to 1 — C U- X 
rj* -r X X to to 

c c d c o o 
O G © © C O 
to to to to to to 


OCNCOVCCM 
m t: c a co to 
’t'tXMO t o 
to COITTNN 


CINXN . 
co co o. 05 r» i> 

t'- t'* !>• P— 05 05 

gggggg 

to to to to to to 


OONxfOJM 

»o 50 x © © c? 

05 05 X CO c C 
C_Z © t - t - '- © 05 

glgggg 

to to to to to to 


■^(NXCS-^(N 

cm x c x -r © 

X X C4 — 05 05 
X X © © 

gggggg 


s 

E 

© 


S 

C *- 00 

*- ®s 


o 


© 


c c ^ 
o *7 cc 

£«2 

g» 


W CO Ifl Tf fH 00 to 
rH M O CO O rf Cl ^ C5 
C35fNNMCCOO 
. to to 50 co © X X X X 

’ggggggggg 

to to to to to to to to to 

d. 


©npx©X©X'©© 

p- CM y © Cf? *— 1 CM O —• 
OiCOlCldCCCO 
. to to 50 co 50 X X X X 


■ggggggggg 

tOtOtOtOtOtOtOtOtO 


CM to I'- O to X 
© © hH i-h © © 
t > - l " H X X 

^ to »o co co 


eo o n 

-«ptOOOI'Cfl 

^■'•XNtOtO 

§ np hp -p © © 

ggggg 

to to to to »o to 


V^OCI-toS 

to to to *o t— r>» 

88SSES 

tO tO to to to to 


g NCOC^'P 

CM X co 
CO CO 05 C5 !>• 

C5fl> 


CO ^ «C 05 05 t^. 

SorCuSo X X CM — Cfc © 
co co t>. 05 C5 t' i" x x o> o 

888888 888888 

to to to to to to to to to to to to 


05 O O 05 CO X 
^lOCtOtON 

l- t-' — X x 

§ np © © © © 

ccccc 
o c co Q © 
to tO © to to © 


V -r CN C C X 


TTXXtOiO 1-OCl' 'OO O O O 05 (>• N 

*r 7 -r o o tctou; tONN ac» 

gggggg gggggg gggg== 

» © © © c -- “ “ - - 


to to to to to to to to to to t 


CC to O C I' 
05 O X CO C O 

§ 50 «- o; 05 

ggggg 

©©©©©© 


© © © CM X *-h 

X X — X CO to 
X X CM — 05 05 
M^XXOJOS 

gggggg 

to to »o to to to 


CM CM CM CM CM CM CM CM CM CMC 

HHHHHHHHH CMC 


4 CM CM XXXXXX CM CM CM CM CM CM to tO tO tO tO tO t>- f- f- S'* t>- P- CO CO X X X CO 

4 CM CM f-H I-H f-H f—< f—( .-H «“H f—I f-H f-H *-H f-H HMHHHH f-H »-H pH f-H f-p pH 


a 


fe 3 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 

1 1 1 1 1 1 

1 1 1 1 1 1 

1 1 1 1 1 1 

1 1 1 1 1 1 

1 1 1 11 1 

la 

B 


Chro¬ 

nom¬ 

eter 

No. 

1841 

Hp Hp "*P ^P >lp -P ^p ^p 

X X X X X X 

t>- © © © 
X X X X X X 

© © © X X X 

HP HP HP © © © 

© © © © © © 
hp -p -p -r *r Tp 

©©©©©© 
X X X X X X 

gggggg 

F-< ^H —-I —^ ^ ^H 

45 

1 1 1 1 1 1 1 1 1 

++++++ 

++++++ 

++++++ 

++++++ 

++++++ 

++++++ 

'O 

£3 

*5 

K 

Chro¬ 

nom¬ 

eter 

No. 

1823 

©©©©©©©©© 

1 1 1 1 1 1 1 1 1 

©©©©©© 

++++++ 

©©©XXX 

1 1 1 1 1 1 

,-H f-H f-H O © © 

C4 CM CM f-H »-h 

1 1 1 1 1 1 

©©©©©© 

I-H «-H — — « ^H 
Hp Hp HP Tp HP HP 

1 1 1 1 1 1 

— — — — f-H 
©©©©©© 

1 1 1 1 1 1 

© 


is 

CM©CMhpCMXhh©© 

X CM CM X I-H I-H 

HP © © CN. © © 

©©©©©© 

H X © HP Hp HP 

x©xxrntH. 

X CM © X © X 


© I 

Jr u 

P- co 


I+++++ I+++++ ++++++ 


++++++ ++++++ 


5 


o 

a 


E££ 

£as 


«0«5®0^0M» 

H 

+ + 


+ + I I + I 


cc *■. n *-* Cm 

+ + I I I I 


II I I I I I I I I I + + + + + + I + I + + 


(M CC CN C 

+ 1111 


£ 

c 


©CfcOOO — OOCS 0000 — 0 ooocoooo— o — — o. 


oooooo ooooo — o oo —o —— 


I II I I I I I I I I I I I I I I I I I I 


I I I I I I I I I I I I I I II I I I I I I I 


■8 

•u 

1 

u 

0 

0 

Chronom¬ 
eter No. 

1841 

s. 

0.5005921 
.5005942 
.5000294 
.5000288 
.5000268 
.5008009 
.5008053 
.5008029 
.5008040 

.5004697 
.5004668 
.5005076 
.5005084 
.5006829 
.6006842 

.5004418 
.5004409 
.5004762 
.5004748 
.5006527 
.5006541 

© x hp cm -h 

Hp © CM — © © 
©©©©©© 
© © © © t>- 

gggggg 

©©©©©© 

.5007350 

. 5007849 

.5007728 

.5007720 

. 5009489 

. 5009497 

. 5006880 

.5006847 

.5007246 

.5007183 

. 5008890 

.5008929 

.5007730 

. 5007743 

.5008144 

.5008122 

. 6009888 

.5009891 

S 3 

5 

*11 

© 

Chronom¬ 

eter No. 
1823 

s. 

0.5005937 
. 5005952 
.5000324 
. 5000305 
. 5006309 
.5008055 
.5008065 
.5008035 
. 5008034 

.6004769 
.5004738 
.5005164 
.5005158 
.5006895 
. 5006927 

.5004510 
. 500-4484 
. 5004868 
.5004853 
.5006613 
.5006631 

.5005628 
. 5005619 
. 5005999 
. 5005984 
. 5007742 
.5007742 

.5007516 
. 5007486 

.5007888 

.5007873 

. 5009621 

.5009647 

.5007062 

.5007015 

.5007424 

.5007369 

.5009046 

.5009117 

.5007900 

.6007905 

. 5008.306 

.6008278 

. 5010029 

.6010M7 


© 
O H 
t-1 2 

Ph CO 


S -^CO^C^^OCM- 
tQOCStQOCOCt 


;s 


to © to to to t 


i-< hp r>- x x x 
co to to »o to to 


eg s 

© © 3 

S-i e.*-* 


o 

c3 

13 

-J 

o 

EH 


o — 
C c3 
© > 
•a hi 
— ® 
o -p> 

c 

o 

o 


as 

a 


X X -£ © pH X ©Oi.-« to CM to NCHCCMO CCir.MOOO ph .p Oi © Hf © 05 t>- CO —■ CM c 

^CON-hthNCOOO I'-C4N«tO X’POCCO tO«tC05«-0 OiCC-Xh © © 05 hP Hp 0505C0r~<et 

O ~ d to to to to to to to tc to OCXXXXX CM — CM CM f—J d © -p © Hp cd Hp ^ X to to tot 


jj*»00O5CO0CC.NC5M 05 C5 

gHHHHHHHrtH »—< pH 


C5 C5 ©5 O C5 C5 

CM i-h i-h 


< hp © r^. r-© r>-©©x©© r»x©xx© coxxxox 

(HHHHH MrHiHfHrtH i-« pH pH pH f-3 CM f-i f-i r-i CM 


NM000 050 
—« «—« CM CM 


J CMhOCCM^PCMOh 

^lotototdtotototoid 


O C O C CM 05 
td to to 


OOOOr-tCM 
to to trj td td to 


C35CM X 05 O 

^5 »d td ^ td »o 


© *■“• 05 X CM © OM»f CMMCO 

to td td td td td id td td td 


© r-l ^ CM ^ 

td td td td td td 


A i£H 

•C O I- ^ 
Oc ©PH 


CM © X CM © to 
X X © © © © 
tO tC ^P CO M 


(Or^iOOMCM 

© © CM CM X X 

to to to to X X 


•-* 05 CM P5 to r» 
to ^ CM CM CM CM 
T Tf -r -M" CO CO 


CM X CM X CM © 

C5 to to to to 

dd'tHdd ed td td x i-H © 

^ f CM CM © © cd ^’J'XX 

X X X X CM CM X X X X CM CM 


44®M 
2 EZ N 

55 p 


CtOOOON 


x © -»r 5 

X © c 


X © X 
CM CM X X © © 
lOiCV vwx 


s 


N ^ ic X N 
io —< — t>. 

© © to x x 


© © CM Tp* © © *-• X ^ t>-CM 

•H’© X © U5XCMNXP* 

x^r^ocd© -*y © rd 05 cd 

xx — — © «o ©©xxr^u- 

X X X X CM CM XXXCdCMCM 


© © CM © © 
— © © Tf -»9* 

XX X X CM CM 


C3 

o 


. X 

^ I 

r>. c 


© _ 
ci,S 


© 

© © © c^> r- 


CM 

CM 

I 


• X 
•CM 


r>- x x cc 03 © 

CM CM CM CM CM CM 


CMXXX^^ 
© t>» f'* !>• X X h«h«hh 


05 • • © • 

I-H • • CM • 

X © © ©© g 


tCbCtL SC t£tctc$£t£ 

D33333DD3 


t£ 6£ fcfl sc SC fciO 
3 3 3 3 3 3 


fcJO be $£ SI SC SC 

3 3 3 3 3 3 

<<<<<< 


be tc tx tc £X fcfl 
3 3 3 3 3 3 


3.C.C.3.C.QI 
ovvvoo 
CO CO C/5 CO CO CO 


3.Q.C.C.C.Q, 

C> 41 ® O © C5 

CO CO CO CO CO CO 


CL CL CL CL 3- CL 
® a> a» ai ® © 
CO CO CO CO coco 


11 


OOQflOOflQQ flapROQ CCQ2QP QQOQOQ OfiQQOP OOQQQP PODQQP 


s = l 

0 . 1=2 


©©©©©Tj*»rTp*Tj< 


© © © © It* HJI 


© © © © TJ* 

<<<<<< 


© © © © HP ■*« 

<<<<<< 


© © © © pft 

««« 


© © © © HJI 

<<;<<<< 


© © © © HP Hf 


fc£ 

.9 6 
££ 
CO 


H CM X ^ © © © t"» X I-H CM X HP © © I-H CM X HP © © i-H CM X np © © 


I CM X HP © © h CM X Hp © © HCMXHptO© 


1 

1 

I 

3 

CO 


5- 

o-i 
® . 
BH 


o2 S 


•gs 

o . 

MJ 

>5^ 

V • 

S3j5 , 

hw r 

rt u 

z 


<fl s 


o\ 

p» a 








n • 

I-H &0 

*-» o 

do 

z 


*3 

03 J- 
O © 

© a 

i 

ic 

L=C © 

I ;£ 

5 • 

z 

►sT 

p 6 

C as 

s-is 

3 j 

►si 

J 


2> 
hH tD 

rH 

—1 

dfi* 

’ w 

oZ 

d! 

z 

z 

Z 

































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


15 7 


Is 

«0 <-H 


0*H 

rH 

CO»H 

co 

•H 


S3 S 

c3 8 

Sg 

S8 

to8 

a 

fin 

05 11 

o d 

I-H 

S3 

05 Tl 

in 

in 

SO 

g-H 

i 


o 05 C© —< 1C 00 

CO CC’ 05 OC' CO 

05 05 05 05 C5 05 

MNC0MiOC'J'f0305 

CO <M CM CM M <M CO <M —< 

2 §g2gngi°2 

COMMMKMMWW 

00 »-t CO CC <£3 

H o f-4 3 jO 
CM Cl CM CM -M IM 

*-h CM CO TO 

t^. G t 

CO CO COCO CO CO 

CM03OOCOC©O3C©*-'r^'TCCO3'*t*COH© 
H' + TrrooTCCTV+Ot.CX^'J‘'r>OiO 
CMCMCM<MCMCMCM<MCMCM<MCMCMCMCMCM 

(CMJJtOOC 
■'* 't* CC ’T H* Tt* 

co on co co cc co 

OOCO'fHLONCOO 
CO CC CM CM CM ■—< Ohh 
CMCMCMCMCMCMCMCMCM 

03 05 05 05 C5 05 
NNNI'-C'N 
05 05 05 05 05 05 

ococdocoo 

00 oc oc cc X. oc 00 oo oc 

C3 05 05 C7 C5 G3 03 05 03 

ocoddoddo 

CC J J- CC CC CC X X XI 

05 05 05 05 05 05 05 05CA 

^ 5: x >6 ^ 

05 05 05 05 05 05 

O G O O O o 

OC or X or. oc JO 

05 05 05 0 03C3 

dcddddddccccccdd 
oc or cooccccccooocnorcxooceocoooo 

G 05 05 05 05 05 03 05 C3 03 03 93 05 05 03 05 

888888 
003 03 03 03 03 

dcddddddd 

CO rj- S S A CO CO CO> CO 
030>O30S'G©0>O>0> 

.6006591 
.5X6593 
.5006946 
.50069:54 
. 5X8702 
.5008694 

N't'J'W3 O CO W N fO 
<Ot^OOOOOOCOQcOC5 
'T't't’tTXX iCO 

Orc-NNKCON 

COt^CO^COSOXcDCO 

to »o jC ‘O cc n k 

iiiiisiii 

. 5007972 

. 5007992 

. 5006988 

. 5006964 

.5006778 

.5006785 

.5007583 

. 5007579 

.5006571 

. 5X6560 

. 5X6361 

.5006362 

.5007912 

. 5007894 

. 5007898 

. 5007934 

. 5007928 

. 5007919 

.5006905 

. 5006892 

. 5006876 

. 5006858 

.5006912 

.500X98 

.5006688 

. 5X6692 

. 5006670 

. 5006672 

. 5X7646 

. 5007643 

. 5006642 

.5006625 

. 5006444 

. 5X6444 

. 5007822 

. 5X78X 

. 5006937 

. 5X6935 

. 5006942 

. 5006764 

. 5X6782 

. 5X6767 

• 5X67X 

.5006583 
. 5X6596 
. 50X933 
.50X935 
. 5008720 
. 5XS692 

. MOM 72 
. 5X5489 
.5005481 
. 5X5493 
. 5005466 
. 6005825 
. 5X5KX 
. 5X7571 
. 5X7579 

(O-4 m o PH CO lf3 !>• 05 
t^05C^p-iC8jcor^i9«o 

^ ^ ^ x y oc x 
ic ic «c x t^- 

ggggigggg 

OiCiOiCtOiOiOiOO 

. 5007975 

. 5008X4 

. 5006977 

. 5006962 

. 5006783 

. 5X6776 

. 5007582 

. 5007583 

. 5006565 

.5006561 

.5006365 

. 5006353 

.5007906 

. 50079X 

.5007901 

.5007930 

.5007931 

.5007927 

.5006898 

.5006900 

.5006869 1 

.5006862 

. 5006902 

.5006891 

. 5006698 

. 5006681 

. 5006668 

. 5006669 

. 5007647 

. 5007646 

. 5006X4 

. 5006626 

. 5006445 

.5006X9 

. 5007817 

. 5007803 

. 5006937 

. 5006939 

. 5006940 

. 5006767 

. 5006777 

. 5X6764 

. 5X67X 

.5006599 

.50X590 

.5006958 

.50X934 

.5008685 

.500X97 

CCOCCNiO— ^<CCh* 
»OcCXN03'rOCCO 

*1* *7 f if if X X 1-0 © 

f-»C—iC'T05i0'Ti0 

COO'fH^OCCCOCO 

X XX 

IC IC CC ‘O 'O !>• N N r> 

888888888 
lO ‘O O tO to o *o tO iO 

.5007970 

.5007980 

.5006998 

.5006965 

.5006772 

. 5006794 

. 5007584 

. 5007575 

. 5006577 

. 50065X 

. 500X57 

.5006370 

.5007919 

. 500788S 

. 5007894 

. 5007939 

. 5007924 

.5007911 

. 5006912 

. 5006883 

. 500X82 

.5006854 

. 5X6922 

. 5X6906 

. 5006677 

. 5006702 

. 50X672 

. 5006674 

.5X7644 

. 5007640 

. 50X649 

. 5X6624 

.5X6442 

. 5X6449 

. 5X7827 

.5007796 

.5006937 

.5X6931 

.6006945 

. 50X762 

. 5006786 

.5X6770 

. 5X6757 

NNNCINN 

ri H H « m 

1 1 1 1 1 1 

05 05 05 05 05 05 05 05 05 

1 1 1 1 1 1 1 II 

ooooooooo 

1 1 1 1 1 1 1 1 1 

to to iO to to lO 

r*4 rH rH »“H rH rH 

1 1 1 1 1 1 

CO 00 CO 00 00 00 

1 1 1 1 1 1 

OGOOOOOOOOOGOOOO 

HhHHHHHHHHHihHHHH 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

t- 

rH pH rH rH pH pH 

1 1 1 1 1 1 

- 11 

- 11 

- 11 

- 11 

- 11 

— 11 

- 11 

- 11 

- 11 

CO CO CO CO CO CO 
G3 03 O 03 Q C3 

++++++ 

*3<MCMCM<M<M<MC^<M 

+++++++++ 

NNNMMNCJNN 

COCCOCDCOCOCOCOO 

+ + + 4- + + + “f4- 

c- CO CC CC CO CO 

r- r- 

++++++ 

+160 

+ 160 

+ 1X 

+ 160 

+ 160 

+ 160 

GCOOOOOOOOGOOCO© 

GGGOGGOGGGGGGGGO 

CMCMCMCM<MCM<MCM<MCMCMCMCMCMCM<M 

+ + + ++ + + + + + 4- + + + + 4* 

CM CM CM CM CM CM 
CM CM CM CM CM CM 

++++++ 

OOOOOOOOO 
iC iO O iO i-C iO i-C iC lC 
CMCMCMCMCMCMCMCMCM 

+++++++++ 

'T T -O' -T 

tO»OiOiOiO»QiOiOiQ 

COCOCOCOCOCOCOCOCO 

ooooooooo 

<MCM(M(MMCN<M(M<M 

cc CO CO CC CO cc 
<M CM <M CM <M 

CO CO c© co co co 

IQ tC O lO to lO lO lO ‘O to to lO lO lO to lO 
<M<MCMCMCMCMCMCMCMCMCMCMCMCM<MCM 

03 03 03 03 0> 03 
CM CM CM CM CM CM 

OOOOOOOOO 
h* h* t'r N h« h* t'- I s * N 

1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 

++++++ 

+ H""F + 4- + 4- + d-4* + + 4- + + 4" 

++++++ 

+++++++++ 

CO 05 00 C5t>» 

IftlOCO Ot^COh-CD 

lOCOCOOMONOSK) 

22 ° £2 00 ° 

GOri'fN't 

HM rH rH 

GiOOGOMrHf'-rTGrH'TOCGCMGCC 

CDOOCJHN 

pH pH 

OrH'TCOOSOpHCMrH 
pH rH 

++++++ 

+++++++++ 

+++++++++ 

++ ++ 

++1+++ 

++ +++++ +++++++ 

++++++ 

+11+++++1 

NMCCOMO 

05I0ONN0C 

1 1 1 1 1 1 

c^—.lOCOCCCJ-iM* 

777777777 

^p-OiCCCiONOh* 
CC * N CC 03 tc 1 - X h» 

7T7T7TT77 

M C IC tf h. O) 
«5 TT cr t- CM co 

7T77T7 

CD CO or . CO O CM 
Tji 03 CO CO CM 00 

7 17 7 7 i 

hhOOXO'TOiO<DMCXhNOO 
IOCS'* CM rH XOncOM*^'fh. 

1 +++++++++11++++ 

+ 59 

+ 94 

+ 100 

+ 110 

+ 109 

+ 96 

03 03 'T 'T !>• O CO *© 
coocrior-'.'TCMp-'CO 

050 —« 05 — O 

1 1 1 1 1 1 

030 0>"05hOO>0 

M H iH 

i i i i i i i i i 

OO^H—h-^>-hC5'—<0 

1 1 1 1 1 1 1 1 1 

O Or-t CO o o 

1 1 1 1 1 1 

C3C3 O Gr- CM 

rH rH rH pH 

1 1 1 1 1 1 

OCOOOCJOCOJOr.wOJOr'O 

rn rH *H rH pH pH pH pH rH rH 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

03 03HC300 
rH rH pH 

1 I 1 1 1 1 

0303003000030 
pH rH ph pH rH 

I 1 1 1 1 1 1 1 1 

. 5X6597 
. 5X6568 
.5006923 
.5006924 
.5X8715 
.5008697 

.5X5437 
. 5X5442 
.5005476 
.5005473 
. 500.5472 
.5005795 
. 5X5754 
.5007525 
. 5X7569 

. 5X5793 
. 5005787 
.5006144 
.5006128 
.5006169 
.5007875 
.5007902 
. 5007887 
.5007899 

. 5007978 
. 5007985 
.5007015 
. 5006979 
. 5006759 
. 5006767 

r- g cm cr cm *h 

In- N CO f- CO CO 
ic 1C to lO CO CM 
Nt^’XJOOO 
G G G C O G 
G O O G G O 
iO iO lO iO IQ iO 

. 5007720 
.5007664 
. 5007631 
. 5007695 
. 5007732 
. 5007711 
. 5006701 
.5006711 
. 5006602 
. 5X6579 
.5006729 
.5006749 

.5006470 

.5006452 

.5006437 

.5006415 

.5007385 

. 5007346 

. 5006325 

. 500X06 

.5006125 

. 5006136 

.5007313 

. 5007275 

. 5006423 

.5006452 

. 5006428 

. 5006285 

. 5006327 

. 500X19 

. 5XXX 

. 50X748 
. 50X697 
.5X7083 
. 5007058 
.5008815 
.5X8837 

ICOX'TXXIO'T 3 
M CJ X C O -4 C Cl O 
CCCCCtCl^CCM^X 
io tc to tc o c ^ t'* 

gggggSggg 

10 »010*010»0»010»0 

OXCOlO’l'O'l'CON 

CDM*t'-C'C05l''N 

ace. crcccoccco 
ic 1 C QP CC cc cc £ oc CO 

ggggggggg 

iOiCiOiC»CiC»Oir;io 

03 CM 0C rf rH 
O 1C CO t-p 'T X 

rH rH CM rH C3 CT3 

cc CC’ i - r-- co ■£> 

G C C O O O 
G G O G O G 

ic to tc Ifl IO to 

.5007733 
. 5007672 
. 5006728 
.5006731 
. 5006478 
.6006452 

. 5007908 
. 5X7827 
. 5007799 
. 5007879 
. 5007900 
. 5007870 
. 5006890 
. 5006S69 
.5006790 
.5006746 
. 5006924 
. 5006939 
. 5006624 
.5006648 
.5006616 
. 5X6595 

.5007580 

.5007538 

.5006538 

.5006502 

.5006320 

. 500X44 

. 5007503 

. 5007448 

. 5006603 

. 5006624 

. 5006613 

. 5000460 

. 50X516 

.5006505 

. 5X6474 


S h* g h* co o 

to td tO t© © 


oooir^cccooocooco 

kO iO U5 »C >0 »C O iO 'O 


03000X^05^10 05 (NM'tH-Ttt COM‘00'-'05 
lOCOiOOiOiOiOiOlO 10 lO CO O O O lOiCOOiO^ 


t^crcor^'-'*-'coofC»-*05crr^^Ht^-Q 

lOifiOOiOOOtOcOiOOCiotOiOO 


MXCOOlNO-H cm 
CO lO lO lO lO lO iCNOi-OOtO^OO 


JCOCCNOJ 

n<o«(&o6 


C»OOOCO(Ch-hO 

catch-WOJONN«5 

cr* oc oc oc cc 


C5COC 05CCCC (NX< 

odocosoGosocososos 


OC ■'* CM -p* CM CM 
CC CO 'T *-h © CO 

oo oc* 05 o; cd od 


0C 00 OC t>- G tocCCMCO’'*'* , 'J 4 'TeMCM»OtO , 't«eOC©CO TO CM CM CM CM CM 00C>-00 0C00O5O5O5C5 


00 050 00 05 00 

f-l M CN H iH H 


■'*050005000500000 

hhhhhhCS"'H 


h-0500>—t 03 OC G GO 

r^rHCMr-iCM-HiHCMi-H 


05 05 05 CM 05 05 

rH i—t rH OJ rH rH 


oo c 05 os 05 cm 
«-h cm rH r4 «-4 cm 


00 05 05 00 00 00 00 00 05 05 h* 00 00 05 00 00 05 00 00 05 00 G 05 C5 05 OD OC 00 

*“8 r-i r-i rH 1-4 rH r-I r-i I—I r-I r-« CM rH p-i i-4 rH f-I rH iH H »H rH PHrHrHpHrHrHpHrHr-i 


!HM*OCiCO 

t© »d »d *d td »d 


id»d»dtd , 'T»dtdtdid 


MO*wwwow'r 

td*d«dtdidtdtdid»d 


C 05 W to 05 OJ 

id •'* *d td ** 


id id id id id 


lO'TNiOCOCO 

^•H(0>0(0 0) 

di4-'nt4i4 

r>» cc co cc cc oo 

CO CO CO CO CM CM 


5 CM CO 05 C I>* CO 

doit^NN^idcid 
g to *o *o to CO CO CO CO 

'trT'T'r^’t'rcOM 


> to CO '* C5 c 

cm cm i ^ oc *d cc 
WCCOCO<-"—’HH 
■^'Trr^'TCOCOCOCO 


'TO O 05 


coco coco cm cm 


Tt tooX O 05f o 

5 TTrt , 'T , CO — —' CM CM 
'TTr'T'T-^fTj'COCO 


j rr 'f r- o co o c 

d-vccNdddd 

wNosaoir-Of-iH 

■'T'TCOCOCOCOCOCOCO 


CO CO cc 00 C C5 
HHlOlON® 
CO CO CO CO CO CO 


O CO CC CO CC CO 
OC'C'fC lO 
CO CO CO CO CO CO 


ONHCIOCO 
CO CO 00 CC 05 C5 
OC CO CO CO CO CO 


OCIOOXOCINOO^NHWNO XhNOMO ONhOJOhNOCS 
-^ididid - rf'ididididid»dididididid -* id id id td id id id «d h* id *d id id »d 

CM O CO lO 'J’CC 0005 C*OW V 
O CC I'w 05 CO 05 CO*-it'-OCOCOCO'-tCO 

os c *d d x n oi 'T 05 oc os oc id g t-- 
cotcooco ■* 'f xx,oc o; 05 C5a; 
CO CO CO CO t* CO CO CO CO CO CO CO CO CO 


cc to o - o 
(M CM I'- I'- OC CO 
CO CO CO CO CO CO 


CD05f-«r>-COOOCOrTOO»-‘»-‘Qr^CCOC05 
M ^ C T N -O C N N 

COCO CO COCOCOCOCO COCOCOCOCOCOCOCO 


CM O C M XtOOd^CCWcC 

CO ' 05 O *—■ O CDH I-i 0> i© i© CM 00 G 

e’ cm cm id g ■<* cdcdosf^cci^^rjJcd 

COCOCOCOC5C5 COCOt^-f^-I^-CX/CCGCCO 
CO CO CO CO CO CO CO CO CO CO CO CO CO CO CO 


;«S88 JJS 


lO 
• I 

3 CO O T ^ »0 lO 


i ^ J, J« cd 


CM CM CM CO OC 00 OC 03 03 


p.aa&c.a 

$ a> v o & $ 
GGCGCGCGCGCfi 


ooooooooo 

ooccocooo 


ooooooooo 

COOOOGCOO 


-4-i -H> •*-> 

oooooo 

oooooo 


00 • *05 • 

CM • • CM • 

r^- cc cc of: C5 05 

CM CM CM CM CM CM 


+^> 4-- -t-> 

oooooo 

oooooo 


ti 


CO 
(M 

©Icmc 


r>»i^t^oooo 05 co co co 


©5 

to 'T '*r 4* ift 

CM CM CM CM CM 


> >>>>>>>>>>>>>> >>>>>> 

o ooooooooooocoo ocoooo _ 


>>>>>>>>> 

ooooooooo 


fifiQfiQfl 

qoqqoqcqq 

OQfiOQflfiOfl 

PDOOQO 

OOOOfifi 

BaflQClfiflQfiCfiflflfifiO 

PQQOQQ 

a 

a 

a 

a 

a 

a 

a 

a 

a 

© G to tO T "T 
<<<<<<: 

COGGGGiOtO'f'T 

<.«««<< 

OCiOiOiC'f'C'f'l* 

<<<I<<3<<<3<J 

cqpcc:p:m» 

H* H* to to G CO 

j£(2C3 2:C£CQ 

^Hj»Tt*^*rt*'TGGGGGGGGGG 

tJ* '* tO G G G 
CGCCCQCQGPQ 

'T'TiOGGGGGG 

K«pqccacacmn 

rH CM CO 'T »© tO 

rHCMt'-00O3CO'T»O© 

rH CM CO 'T © »© <0 t'r 00 

rH CM CO 'T tO G 

pH CM CO 'T GG 

HNHCMrtl'CO^OOOOOOf'OO 
pH pH pH rH rH rH rH 

»-H CM CO tOG 

fHCMCOM'OtOOh.OO 


*!3 
® p 


OH 

d£ 


CO fe 
.p 

.£-■ 

oo r 

^ c§ 

dfi 


© fe 
(u 2 
•c P 

!l 

2* 
*"• £ 
. o 

OH 

£ 


tuO . 
p © 

F 


oS 

SC 


S* 4 

T3 

p p. 

2 J3 

o ° . 

s s 

o2!S 

fc 


'O 

p 

h-I 

o fl 
tx h 
(3 « 

ot* 

s; 


- ® 

t*>g 

§1 

” . 

d^ 

* 


-*-> • 

^6h‘ 

oS; 

sc 























































































Pendulum observations and reductions —Continued. 


158 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


£ 

Sat 

Cl 




d 

8 


*3 

© 


o 

o 

“8 


N ^ cr. OJ IN (N r / IN (N C to C C/) N 
(/: I' CC OC »-* (N OJ ^ O'* f COL r O 
CS^M<NC'JWCO^COCCC«'! < 
•CC«OC(OC'«OCC^CMXX 

j 888c3cc5Soocco§ 

iO iO O iO *0 O 'O c *o >o >0 iC 


VCt-OOMtO-^OCONCiNOL'J 

w ^ M O w tC w (N »-o in ro o co ir; o 

'—'C'JC^C'l©©©©©© 

(yDooococcocoi-i^i'-i-i-i-i-i-i- 

888888888888888 

iOCiO‘O‘OOOO‘C‘O'O‘O‘0‘0‘0 


rf *f *f M* C4 CO 
O'! co C4 co —« 

--CfNCMiN 

X x x t ~ 

o © o o c © 
© o o © o © 

U)tOiOiO>OiO 


c o 
O u oo 

5- G 

<d 


CJNCOCIh-COOOOTpcOOrtNO © 
XM-O.COCCOfNCOW'toy © © 
0404C'4C4P4X©©©©©©XX-*« 
• 5C C O C (O to O to (C tc tc <C CT' x-o 

d©oo©o©ogg © © © © © o 
oooooooocoooooo 

lOiOiOUJiOiOiOiOtOiOiOiO^iO'O 


CS—tCl'-C^'5r<M<NT?<cO 
hhhhh(NW!NO 

ixcr CCCOGO* - * • 


t'* I- l>- I-» I'- 1^ 


I00i0i0i0i0icu0>0i0i.0‘0i0i0ic 


|-w CO r-< 03 CC 04 •—< 
‘ HHO*NWN 
t^COCOcCI' 

2888888 
Cv to lO lO *0 iC iO 


4 04 C3 -** 04 r 

»-« _ _ 04 -4 oi © 

a C oc co. t- r- r- {> 

8888888 

UJUJifliOOWiO 


CO 04 00 © 00 CD © 

m ’ thhOJ 


1 

Chronom¬ 

eter No. 
1823 

s. 

0.50062% 

. 5006273 
. 5006297 
. 5006263 

. 5006276 

.5006321 

. 5006615 

. 5006629 

. 5006649 

. 5006617 

. 5006639 

. 5006660 

. 5008374 

. 5008387 

.5008414 

.5008122 

.5008110 

.5008141 

. 5008098 

.5008116 

. 5008163 

. 5007214 

. 5007227 

. 5007257 

. 5007019 

. 5007032 

. 5007058 

.5007027 

.5007050 

.5007070 

1838 

.5008153 

.5008130 

.5008070 

.5007214 

. 5007244 

. 5007220 

.5007023 

.5007024 

.5007031 

1836 

.5008109 

.5008122 

.5008128 

.5007238 

.5007235 

.5007213 

. 5007007 

© 

O 

c9 

Flex¬ 

ure 

xxxxxxxxxxxxxxx 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

XXXXXXXXXXXXXXX 

1 11 1 i 1 1 1 1 1 1 1 1 1 1 

H w* 1-4 1-4 *—« w4 1-4 i-4 

*“H ^4 r4 r-4 r-4 r-4 44 i-4 rH 

1 1 1 1 1 1 1 1 1 

f* 1— 44 44 1-4 44 44 

1 1 1 1 1 1 ! 

a 

© 

Chro¬ 

nom¬ 

eter 

No. 

1841 

00C0Q©idididLdididC©0 
C O O C C © |Q |Q Id -d 'O id*N M- 
-t^t^TfcdMCCMMMCdCCCO 

©©©©©©©©©©©©©©© 
©©©©©© i'^r'-i^©io©*o©*o 
'xrxr^.xrxr-xj'XXXXXXXXco 

+++++++++++++++ 

S 04 C4 © © © _ _ 

U* © © © (M (M <M 

C4 C4 04 X X X w 

eo + + + + + + 

®,i,„_iQOoa5 

W V'T'TKCCO: 

^+++++++ 

© 

T3 

33 

4-4 

3 

« 

1 

• Chro¬ 

nom¬ 

eter 

No. 

1823 

XXXXXXXfOXX CC CO CO eo CO 

xxxxxxxxxxxxxxx 

^•TrTr*frr»i'ccppMCtNN<NC< 

+++++++++++++++ 

®000«XXNNN 
c? 1- !>. l>. M N (M © © O 
QQ--r*-r-^LO©©iO©© 

H+++++++++ 

^©©©0404C4T- 
00 1-* 

4 1 1 1 1 1 | + 


CO & 

<v H 

JF ^ 

P-. W 


P4»-ixo4©p-<o4P4'^xxxio—<© 


++1 I +11+++I I + 


I+I++I++ +1+++ 


CO ^ 04 co 04 O CO 00 WMHOWO»0 

1-4 »—* •—« 

+++++++++ +++++ + 


| g£ 

h 0.5 


L'SONh-CO'^OJiO'-i-ftOOJNOC 
(N T}* M (N C »r. ^ o Tj« -/j ^ X 

++++++++++- 


01CC»OOC(NN«OiO>OOCCm^-h 

coooocsoor-^-r^rcscoCM-^ooco 

'TTriO'TTr'rvrrrrrrrrTrTj'ccco 

+++++++++++++++ 


’T M» OJ <-< U5 o N Oi 
OCOrH^rHM^C^ 
04CM04XXXXXX 

I I I II I I I I 


CO *-• CO 

CO -r *«r 
CO CO CO 


I I 


NNTPT?- 

i-O io T r- 
CO CO CO CO 

IMI 


o 

u 


ooJOccroac^cc-HNr-i-HC^ coociojoc-ooconccax 

I I I I I I I I I I I I I I I I I I I II I I I I I I I I I 


00 3JOOOOOC5NO 


I I I I I I I I I 


CMOhOM- 


I I i I I 1 I 


T3 

© 


o 

© 

3 

3 


© 

Ah 


J o 
2* 




fl- • 
c JhOO 

!a ^ 


X © ID «3 X C^d X ^ X CO 55 5© 

co co co co ^ or on oo co op 05 »o »o *o 

.iCi0iC*C»0i0i0i0*0O*0i0h*NN 

sooccr-ooocoocccoro 

©©©©©©©©©©©©©©© 

lOiOiCiOiOOiOiOiOiOiOUJiOiOiC 


oeoeocortwiONOoocorpooo 

C'VCCCOiOONWCCCOOiOoOClCO 
XP4P4040404Tj-'T'rr04 04CM04XX 
ts.t'.t>-t'.h-t^CCOCDtOCOCOCcD o 

©©©©©©©©©©©©©o© 
©oooeocooooocoo 

lOiOiOiOiOOiOiOOiCOiOiCOiO 


©CTNNCH 
K ir. cc N r (N (N 
* — — — 04 04 04 


h co onr N N h. C''C V C' 

*888888—* 
Cv 1C Id lO lO lO o 


S o«» 

c Z W 
o u® 

*- G ^ 


X»OOJCCX‘OX04©X©.--'XXt-i 
•<WOO)CO iO»Ot^y}rHNCO(N 
JCOiOCOOCOOO-HrHNt-X 
; iO O *0 *0 co O O CD CO O N t'- !>. 
>©0©©©©©©0©©G©©© 
©©©©OO©©©©©©©©© 
iC o o »o UJ O iC iO c o O U3 tC c »Q 


o 


© 


JOOCCOCCIOOO^OOOOO'O© 
id v IO >r i> »d tr Id o id © 

t'- 1^- t^* I-- t— I'* cC © tO 'O to to to to to 


id id o >o io >*o *o >d ‘O to >d >d id 'O *o 


©xxx©*-404-><t'cD 
fH rrccooo 

O' © © © © © © X 00 X 
0? r- r- i- to to o 

*888888883 

^ O 'O U5 *0 lO *0 »C ‘O IO 


(fl *“• CO CO CO * - - 

W cc cd ^ <P 

*ocooooS 


00 03 03 05 CO N 

c* LC t"- CO © •—< o © 

CO X x oo i ^ r- r> 

*8888888 

W id Id >o *o »o *o lO 


td © 

© H 

jp 3 

A- tf> 


^»OidOOOCDOcOidid*dOOCCO 


E £ £ 

® © 3 

E-H 


.©i0^r©co©Trt^.©r^.©c^Jco©^r 

^N’TCiHCOOCOVCNNidHJ 


0 eocs—<cscNCNn'co^'^ioiocoroco co 04 co co co ^ ^ ^ ^ -s* »o 10 to 




© 

o 


£ 

© 

G —* 
3 C3 
© > 
T3 l- 
© 
G 

O 

O 


C5 

C 


: r^CC CO CO © SC G> — © Oi 00 f-< 1 -i 1003 OC OO r>-05 © © t>-CO M © CO CM 


t^.©©©©©00©X © © r-( © © © 

cs oi c4 cs cs c4 


JNCOOOCCOCHCOCCOCOCOiO^Ud rH0300H!N(NO'i!NCUZ!030'V 
~ id id id id ‘d *d id id id *C id id id id id^idididiOiOid»Cidid , J'* , P‘did 


■*'t-*CQOiCiw-l<X:C*-*r 


»o »h »-h t» co 

id id id id ifi id >o 


4 i oh 
° gZ’X 
^5 O 1-00 

O r OH 


cj*dco(»or<ci*H{OMCS'»fcoowN 
©coco©©r ^©»-1 c-j ^co03 oid o 


iO©©r^©Trc^o-Jr-co©co©^r- 

idC'-'-HtNOtCidNCd'^CNidHO 


--_ - i S '-'K ^ ^ ^ ^ C^l lO © © LO CO © © x © © © X co CO 

©©©©©©C^COOICIC^C^COCOCO f ^ r- rt ffi rf ;Yi rr^ rr, O 03 ~ d> 
*^^Tf*rj<T}iTfi«^--«T?'Tr-^'«j'rccOCO COCOCOCOCOCOCOCOCOCOCCTrCOCOCO 


»^ © © X © © 
^ dll'- CO i-< N o , 

»*»r^r^o6©©cdv 
m © © © -*r 

^MCCCOCOMCO 


r#5©©OJiO©01© 

“. 

^^^-Md»d»dC 

▼^XXXXXXCO 


4®o« 

£ SZ« 

^3 § u°0 
O c <ui-i 


;c<io©t^xc^©xxrH 
«0 6 >d id N O C CO CO H oq 03 idD »-i r—> o 
Tj’r«TfrfrtTl'rr^^TtiTliTr^)COCO 


‘dOCOCCcD-i©idCON^XNNN 

^^©Xr-iOCvliOt^©^©©©^! 


xxxxxxxxcoxxxxxx 


CO 

03X^t'©©»O© xt^*t^» 
^^Ht—.-.udOio©©© 
^cdcocococccocococo 


^OWCOXMO 
CO 


© 

— 

03 

o 


s! 

Pu« 


rOr} < ' r t* -4* © iO ci 1^- T't X/ X ‘O © © CO'9*Tf'4 , uOioJ5©©cit^-t>-t^-oOX > 

HHHHHHilHHHHrSHnH HHHHHHHHHHHHHHH ©X© 

^ ^ 


© © © «-H ** 
©C3HHHHH 


2 SSS 2 SSS 9 SS 55 SS cocaccccccscccfl 

c? rt C« C3 « © c3^ c3 o3 c3 c3 O3c3c3cac!3c3c0c3c5c3cec3c3o3c3 

^ ►—s r—> r-^ i—j I—s i - 5 r-j ►—> >—5 (—3 r—3 I—3 »—3 (—3 1—3 >—3 >—3 >—3 H-3 ►— 1—3 >—3 >—3 1—3 (-3 H-3 H3 >—3 


333333333 

3-3(—3H-3l-3>-3»-3>-3H^H-3 


. . .co 

.04 . .04 

«-< 4« 04 04 ci CO CO 
04 04 04 04 04 04 04 

>?>?>? >?>?>? 
3 3 3 3 3 3 3 


Q^ftfipqQpqQQQQQP PGPlQqQCPlpQnQClGq PPPPPPPPP QPPQCQG 


3 • 3 
<D 3 w 

P-.-5 


tOcococDCCidididididid^+"^ *r ^ 10 10 *o © © © © © © ■»r^r^?'©©»o©©© 

««« Ke^aMawannpqeeras) nc3a«e«s;p3M 


■xr ^ ud 10 uo © 

ppppaapfl 


tc 

.E o 

CQ 


•-« 04 X , xji *C © © ^ 04 CO X © H04« , »ld©N0000^04MxjMd fH OJ CO xf id CD N 00 O HNM VidON 

^ ^ ^ '“X ^ HHHHHH 


\> 

<35 

tr. 

JD 

O 

T? 

C 

CC 

a 

o 

♦» 

09 

44 

GO 


»1M 

■cf- 
Q O o" 

c S 

fl«§ 
o cO . 

tc a >> © 

a — ® a 
^ S C S 


* 


Uco 


r.g ,• 

® . 
.•OH 
Q £ ®- 
O S 

Cfll 
o c O . 

c *. ® a 

xx W ✓ c 

^ g h « 

Soco^ 



jp 

© o 

cs® 

o 5 


P’Co — 
o ® 

© o 

o c y ^ 

c o 

cd > 

i-i ^ t_ 

+4 2 r? 

SomO 

«ulo 


























































































































































6007015 | .5007018 i .5007016 


INVESTIGATIONS OF GRAVITY AND ISOSTASY 


159 


is 

CO il 


© *-« 

88 

Is 

Is 

a >1 

85 

© Tl 

ii 


S5 

05 T* 


So 

05 T1 


S3 


MO'T f! O O 1- W N m N CO c. r/) 

CM — CM <N :M CO CM CM CM f- rvj 

oooc oooooooooo 


<N §5 § 05 00 00 00 

o c © © © © © 

§ s §? s s s § 

05 05 05 05 05 05 05 


OxfH35 
f- oo CO —< 

© o c o 
goo© 


OOOOiOOOOODOOOOtDOC« 

fO’r'fTrNco^MiCd-rco 

i>» *>. t>» t>» *-• t>» c» i — r>- t ~ i^-1'- t"* 

88oocoooocoBc8 

lOiQiOiCOOiOiOiQiOiOiOiOiO 


COO't^CCM 
I'- © 00 05 CO 
CM CM CM O O © 
r- i — 

8SS0S8 

lOiOiOOiOlO 


SSi 


* 04 O O 05 

O C C 04 04 04 
t'r 1- I — !■* t ^ It. 

888888 

lOiCiOiQiOO 


04 05 00 c 
or 00 05 00 x < 
00000 c 


t''- 05 CO ■’T CM •—« 

t'-r'oco t- o- 
oc 00 oc 00 00 00 

05 05 05 05 05 05 
i- t- r- r>» 
05 05 05 05 05 05 


05 04 CO O CM CM 


8S2SSS 

o N N 


^O^CCCh 

S GC N 

O O 04 04 CM 
r- r- t- t^. o. 

888888 

©©©©©© 


CO 00 OC 04 CO Tf 
CM • C >0 CO CO 
© © © 00 00 OO 
o. t>. 


MOXV© 



O O 05 CO 
CM Tf CM fT 

0000 
t'-1'- i>- r- 

3888 

© © © © 


F-O o ^ ^ 05 o CO 40 00 CO ^ 40 CO 04 
VCOS v’TO'O 40 
^jTrTfTfTfTfTfTfTrTfCMCMCMCMCM 04 
^nnnM'Nnn r- r^. r>» t>- i ^ r>- i - 

2SB888888888888 8 

“©©©©©©©©©©©©©© 40 


© © o- O —4 CM 
OC l>• 40 05 © X) 
CM CM CM © © © 
U- I- I - 

888888 

40 40 40 40 40 *0 


40 © 40 40 Tf 05 
OC' OC I— 1- f- 
© © © CM CM CM 
O- N l- N N 

888888 

40 40 40 40 40 40 


CM © 00 © --f © 
05 CC 4'* CCN iC 
© © © CM CM CM 
t» i- i- r>- r- c- 

888888 

40 40 40 40 40 40 


t-H 40 »0 © 40 © 

cm —< • -<r cc ■*r 

© © © 00 OC 00 
r- i ^ i'- 

888888 

40 40 40 40 40 40 


CO © 40 © © 40 

*1 f- fT FT O —I 

n h- ci oi © 
Nt^Nr»NN 

888888 

© © 40 © © © 


FT CO © Tf © 00 

oc © 5 © © ^ 


5 CM CO CM 
; © © © 

. r-~ 


^rr-©CM©r>-*-<cof''-C500'** , ©^J < 
co © © co •*tcoco'^ , co ©©*0 40© 

^•'»r-»rTrrp'<r-TTr^'n*CMCMCMCMCM 

*88888888888888 

“©©©©©©©©©©©©©© 


© 

© 


© oo r>- i— © go 

CM Cl CM © —< © 
i - 

Q©o©oq 


Tf © © 00 t". © 

oc 05 © t— oc © 

© © C CM CM CM 
t>* r^. t>» 

88S8SS 

©©©©©© 


I s - © © © © © 

g cr © © oc © 

© C Cl Cl CM 
i- i- 

888888 

©©©©©© 


>C O Cl N H 05 
CM CM © © CO CM 
© © © 00 OC 00 

i - t'- t'- i'- 

SSSS88 

©©©©©© 


CO ft ©t>- CM CM 
CM t—i © i— ft © 
l'- r*» t'- © © © 
t>» r>» 

888888 

©©©©©© 



HHHeHH 

1 1 1 1 1 

© © © © © © © © © © © © © © 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 

© 

1 

© © 40 40 40 4Q 

1 1 i 1 1 1 

© © © © © © 

1 1 1 1 1 1 

00 00 00 CO 00 00 

1 1 1 1 1 1 

t>* t- t>- 

1 1 1 1 1 1 

©©©©©© 

1 1 1 1 1 1 

© © © © © © 

1 1 1 1 1 1 

© © 'tr -*r rr 

’>»• TT •—4 *-H •—* 

Tt« TT © © © 

+ + + + + 

^[^Nh.OCOOCOO©C’fTf 

^©©©©©©©©©rr^rrr©© 

" 1 1 1 1 1 1 1 1 1 1 1 1 1 1 

-154 

© © © © © © 
© *0 *0 TJ4 TJ4 TJ4 

7777TT 

© © © 
© 40 © Tf T}* TJ4 

777777 

Tf -t« Tj» CO CO CO 
©©©©©© 

777777 

© © © © © o 

N t'- N -t V -Jt 

fH H F-* FT FT F 

1 1 1 II 1 

00 00 00 00 00 00 
TT Tf TT © © © 

FT FT FT FT FT fT 

1 1 1 1 1 1 

© © S © © © 

FT ft f FT ft F 

1 1 1 1 1 1 

sfTTNNN 
•—■—<©© © 

+ + + + + 

WooOf^NNNNNCOCOCOCOCO 

W'TW'r’r’rsrw'TTr^rMCO 

H 1 1 1 1 1 1 II 1 1 1 1 1 1 

-138 | 

_t —i —« © © © 

COOOOCI-NN 

777777 

r- © © © 
oc oc on © © © 

1“^ F-t *—• I— t-A 

1 1 1 1 1 1 

Tf Tl* Tl* © © © 

i'- n r- i'-1'-1>- 

777777 

©©©©©© 
© © 40 CO CO CO 
CM CM CM CM CM CM 

1 1 II 1 1 

FT FT f4 © © © 

CM CM CM FT FT FT 
CM CM CM CM CM CM 

1 1 1 1 1 1 

CO CO CO CM CM CM 
F f f CM CM CM 
CM CM CM CM CM CM 

1 1 1 1 1 1 

CO CM < o 

r-4 H H 

©r^t>-oo , «*»Hco©oo©CMr>-CM© 

H f4 fH 

CO 

© © »*H OO © 

H f4 

TJ4 Tj» CM © CM O 

00 © © FH 00 © 

FH ft ft f^ 

N^*h©Nh 

©CO CM ©CO—4 

© © CM 00 CM 

1 + + + + 

++++++++++++++ 

+ 

++++++ 

+1++++ 

++++++ 

++++1+ 

+ +1 + 1 1 

+1111+ 

co—.©©r>- 
00 © © © © 
CO CO CO CO CO 

1 II 1 1 

©t^r^co^r©©©©©©©©—i 
©©OC©©OO^COOOOOQOOOOGO© 
COCMCMCMCMCMCMCMCMCMCMCMCMCM 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 

© 

CM 

1 

© CM © CM TJ4 
•V M- CO CM CM F-4 
CM CM CM C'J CM CM 

1 1 1 1 1 1 

00 —■ © © 00 T£ 

© !>• r- © © 

CM CM CM CM CM CM 

1 1 1 1 1 1 

© F- CO cm CM 00 
© © © OC © 
Cl CM F F F H 

1 1 1 II 1 

CO © © © CM © 
03 © © FF CM CO 
f-» CM CM CM CM CM 

1 1 1 1 II 

©TfFT©cor- 

CM CM CM FT ft O 
CM CM CM CM CM CM 

1 1 1 1 1 1 

CM CM © O Tl« 

hfONh® 

CO CO CO CO CO CM 

1 t 1 1 1 1 

F-l ^-» © CM © 
fH H 

1 1 1 1 1 

1 1 1 1 1 1 1 II 1 1 1 1 1 

© 

fH 

1 

CM CO 00 © © © 

H *—4 Fi 

1 1 1 1 1 1 

t>- H © © © © 

FH fH 

1 1 1 1 1 1 

CM CM © 00 © © 

FtFH fH 

1 1 1 1 1 1 

© © CM © 00 

F H 

1 1 1 1 1 1 

t>-t>.oo©oot>- 

1 1 1 1 1 1 

r^oo© t^© © 

II 1 1 1 1 

.5006977 
.5006972 
. 5006930 
. 5006926 
. 5006907 

1841 

.5007934 
.5007915 
. 5007897 
. 5007923 
.5007892 
.5007874 
. 5007884 
. 5007892 
. 5007883 
. 5007728 
. 5007704 
. 5007691 
. 5007714 
. 5007715 

. 5007705 

.5007701 
.5007685 
.5007657 
.5007465 
.5007466 
.5007450 

.5007519 
.5007529 
.5007505 
.5007686 
.5007686 
.5007689 

.5007534 
.5007504 
.5007442 
.5007646 
.5007628 
. 5007589 

.5007996 
.5008002 
.5008011 
.5008215 
.5008230 
.5008224 

.5008090 

.5008092 

.5008100 

.5008294 

.6008294 

.5008294 

.5008547 

.5008551 

.5008518 

.5008752 

.5008730 
.5008697 


S r^©N© o©©occ -- . - — 

cor^ocr^- a* cr ft cp cc © oc t"- 05 oc © <- 

'O* CO CO CO CO 2 OO © 00 cc C CO CO X «) N N © o t- ~ 

^ r ^ w ^ r>» f ^ [s. [>. ['v i ^ f >. r •• 

88888 *88888888888888 8 

© © © © © 40 ©©©©©©©©©©©©© 40 


X©©Tt<T}’*t 
Tf © CM Tf © CM 
40 © © r- i^* r>» 

888888 888888 
© © © © © 4Q ©©©©©© 


CM © CO CO Tf © 
O ft 05 00 © 00 

r- © Tf *o Tf 

i- t- r- f'- 


© © CO CM CO CM 


^ I ■ — j. _ _ __ _.. © tt o Tf 

© © Tf © © © ©©©COCOCO •—I »-• *-< co co co © © © oc oo r>. 

t- t- 1- r- t>- I- CC OC or CO CC 00 00 00 OC OC OC' OO 00 00 00 OC OC CO 

888888 888888 888888 888888 

©©©©©© ©©©©©© © © © 40 © © ©©©©©© 


68 

52 

53 

53 

54 

©tT.ts»©©cOFTTr©C 30 CMt^©© 

©©©©©©©©©©©©©© 

© 

© 

Tl- CO © CO © 00 
©©©©©© 

© © CM © CM Tf 

© © © Tf © © 

© CO © CO © 00 

Tf Tf Tf © © © 

tr. © CO © CM CO 
© © © © 00 © 

Tf fT © 00 00 © 
40 © © © © © 

© Tf © Tf © l^. 

© © r>■ © © 

© CM CM CM CO 
f CO tt- © TT 

©©©CMCM©©©©©©©©© 

CO H CO H O 05 C 5 0 > C 5 C 5 © tr- © © 

© 

© 

© CM © © © © 

© CC © t}- CO fT 

© CO © © © © 
Tf Tf Tf Tf Tf CO 

CO OO CM 0 C © 

© © N O CC t- 

© 00 © CM © CO 
© © FT CO Tf 

00 © 00 © 00 © 
CO CO CM FT © 05 

©©©©©CM 

Tf Tf CO 0 C Tf © 

V^TT TJ«F 

CM CM CM CM CM 

NNhNCMfffffhfff 

CMCMCMCMCMCMCMCMCMCMCMCMCMCM 

CM 

©©©©©© 
CM CM CM CM CM CM 

CM CM CM CM CM CM 

FT © © © © 00 

CM CM F H FT rt 

© © © O C © 
ft f F CM CM CM 

© © o © © © 

CM CM CM CM CM FT 

CM CM CM CM CM CM 
CM CM CM CM CM CM 

© © © FT © 

COftCMCMC©OhC 5 iChfOC 5 

© 

© ft 00 I s - © 00 

©© 00 00 00 © 

H©Oh-C 3 © 

t >-00 00 FT©t^ 

© © 00 © © 

©©oo©co© 

ft CM ft CM CM 

CMCMCMCMCMftCMCMftCMCMCMCMfT 


CM CM FT F H fT 

ft CM ft ft ft h 


FT F H CM FT FT 

FT HHfTHH 

HfTHfTHH 

CM TT l'- © FT 

^©©^©^©OCMCM©©©© 

00 

© 00 © © FT © 

CO CO 00 CM CM CO 

© l>» © © t>- © 

CO FT CO © CM © 

© © © CM © Tf 

©©ft Tf CO ft 

© © TT © © 

©©©©©© 40 ©©©©©©»d 

rr 

© © Tl- Tl- © Tl- 

Tf © Tf © © Tf 

© © Tf Tf Tf © 

Tf © © © © Tf 

Tf Tf Tf © Tf Tf 

Tf © © Tf Tf Tf 

FT © TT- © Tj- 

CO ft cm TT TJ 1 

_F©©r^CM©CM©f'»CMCM 00 ©©CO 

^J©CO©OCMO©CM©©©©©© 

iHcocococococococococococncoco 

© 

Tf © © CM © © 
FT CO © Tf CO © 

© Tf cm © r- co 

©©©h-t'O 

Tf CM CM 00 CO 

C. © Tf Tf CM © 

© CO © CM 00 © 
ft © © 00 CM © 

© Tf Tf CM CM CM 
© Tf FT © © 05 

© © o © © © 

© 00 © FT 00 05 

OO © ft ft CM 
© © © © © 

CO CO CO CO CO 

TT- 

CM 

CO 

© © 40 © © 

M CM CM CO CO CO 
CO CO CO CO CO CO 

CM CM CO © © © 
CO CO CO CM CM CM 
CO CO CO CO CO CO 

CM CO © t''* 00 © 
CO CO CO' CM CM CM 
CO CO CO CO CO CO 

asssoo 

CO CO CO CO CO CO 

© © © FT fT F 

O © © © © © 
CO CO CO CO CO CO 

co cm Tf © © 

§j § m c 5 

Tl- CO © co 

AT©Tf©Tl 4 ©©©*- 4 ©C<CMCOOO© 

COCO ^C; TT FT <N ©C 5 © N © FT 

CM 

•O’ 

© © N 00 CM © 
FT CO Tf © © t*T 

CM CM © © CM © 
tr 00 © CO © FT 

© oc © cc Tf 

© F CO © F © 

CM CO © © Tf © 

© © © © © Tf 

00 00 © © © © 
CO © © © © CO 

© Tf CO © © © 
© CM CM Tf CM 

oo © co © 

5 SS 383 S 5 S 5 

SblcCNf-O^CCNN^'OiOiO 

'~HfftfttthCMN(NNiN 

»Hcocococococo©co©coco©coco 

40 

CM 

CO 

©TfOTfCOT}- 

CM CM CM CO CO CO 
CO CO CO CO CO CO 

FT © CM CO CM Tf 
CO CO CO CM CM CM 
CO CO CO CO CO CO 

ft co © oo 

CO CO CO CM CM CM 
CO CO CO CO CO CO 

© © © C © FT 

C O FT o o o 
CO CO CO CO CO CO 

© © © © © © 
© o © © © o 

CO CO CO CM CM CO 

© © CM CO Tf © 

ssssis 

July 23 - 24 ... 

July 24 . 

July 24 . 

July 24 - 25 ... 
July 25 . 

Aug. 25 . 

Aug. 25 - 26 ... 

Aug. 26 . 

Aug. 29 . 

Aug. 29 - 30 ... 

Aug. 30 . 

Aug. 30 . 

Aug. 30 - 31 ... 

Aug. 31 . 

Aug. 26 . 

Aug. 26 - 27 ... 

Aug. 27 . 

Aug. 31 . 

Aug. 31 ,Sept. 

Sept. 1 . 

Sept. 8 . 

Sept. 8-9 _ 

Sept. 9 . 

Sept. 9 . 

Sept. 9 - 10 ... 
Sept. 10 . 

Sept. 15 . 

Sept. 15 - 16 .. 

Sept. 16 . 

Sept. 16 . 

Sept. 16 - 17 .. 
Sept. 17 . 

Sept. 24 . 

Sept. 24 - 25 .. 

Sept. 25 . 

Sept. 25 . 

Sept. 25 - 26 .. 
Sept. 26 . 

40 40 © © © 

F+J-j+j+j+< 
o a o o a o 
OOOOOO 

Oct. 13 . 

Oct. 13 - 14 ... 

Oct. 14 . 

Oct. 14 . 

Oct. 14 - 15 ... 
Oct. 15 . 

Oct. 20 . 

Oct. 20 - 21 ... 

Oct. 21 . 

Oct. 21 . 

Oct. 21 - 22 ... 
Oct. 22 . 

OQOQP 

OOOfiCCQQQaOOOft 

a 

PPfiOfiQ 

floafloo 

popppp 


PflfifiPP 

PPPPPP 

© © © © © 
P 3 BP 3 CQP 3 

©©©©©© »o ©©©©©©© 
( 25 «P 3 H«W 33 aCQ»ca«a 3 Cq 

B 6 

©©©©©© 

©©©©©© 

©©©©©© 

© © © © 4.0 © 

cQScaacn 

CO © © © © © 

p 5 «mmcsn 

©©©©©© 

««pQoom 

00 © © FT CM 
fTHfT 

Tj*©©©r^co©©FTt>»oo©£ 3 co 

F F ft H CM CM CMCM 

Tt* 

CM 

Tf © © t'* CO © 

FT CM CO Tf © © 

FT CM CO Tf©© 

FHCMCO-rf ©© 

f- 4 CM PC'*- ©© 

FT CM CO ^* © © 


tc • 

S3 

Cg 

d> S3 
JXO 
u'-i 

a 

a. r 

2 .S* 

d££ 

z 


•> I 

to > 

|g 

a” 

5 a 

«5« 
n -c 

« o 

!a_: 
oO ® 

Z 


aj 


o 

■P 
a r 
p • 
.20 
r) a 

S3 

r^. 

S-d 

d5 

Z 


too 

Pfe 

4-« _* 

*p 

.a 

00 O 


o* 

Z 


o 

a^. 

§1 

§i 

£>P-l 

*Q 

Si 

o>-» 


o 

a . 
•2| 


p 

. O 
0*"5 
>« 


xT > 

•ti o 

a^ 

®d 

Is 

o 

.tl 

H « 

*ii d 

o-<o 


a Chronometer rates were determined by star observations. 
t> Chronometer 3477 failed to break for the last day’s observations, 
e Chronometer rates were determined from Western Union noon signals. 










































































































Pendulum observations and reductions —Continued. 


160 


tr. S. COAST AND GEODETIC SUJRVEY SPECIAL PUBLICATION NO. 40. 


a 

$ 

3 




©CM 
© © 

© O 

r- rH 

gs 

2® 

© t1 

05 O 

S-H 


sg 

© 

© *ti 


S3 

o 

© *71 


© " 


«e © © © © © © 
^ CD © CD CO CO CO 

feO O) O O O C3 

—. (» [, [ — f ^ 

^050050050 


00)0000 
I" i- i- r^ 

oooooo 


O' O O) © O) © 
I"!'* 

© © O) © O 05 


O) © 05 © O) 05 
C5 05 05 05 05 05 


-■T © CM © CM 
© © tO © CO © 
05 05 05 05 05 05 

05 05 © 05 05 05 
i— i>. n n n r- 
05 05 05 05 Oi O) 


"O 

© 


I 

© 


S CM *rr CM Tt* © 
05lq 

cm •—**—< co co co 

• 00 oc CO OC 00 CO 

888888 

©©©©©© 


Si 


oc' oc- oc or c 

OOCOOCJ 

o o © o c o 

tc to to >o *o 


to to to O to to 


05 *-< 00 O rrt 00 05 CM © oc 00 -tf NOCONO 
OG CO © 00 l"** 1^- »—< •— 1 05 CM .-h CM i-h © © rH © © 
—< -h —(hhh!NCjhOOC O O O t \r ^ 

cccooc xxxi'i-1-tr 5 o^ ^Cr ir 

008880000088 0008cc 

10 to to to to «5 to *C VO to to to iO tO o *o tO tO 


a o . 

Sfe® 

g® 


CO 0 05 tO *t CO 
05 05 I- CO CO 
*h *h 1-1 X CO CO 

. oc 00 00 or oc 00 

*888888 

©©©©©© 


oc © ot »o *0 *0 

COCOCOtOtOtO 
OC CO OC 00 Vi 00 

888888 

© vO vO © *0 *0 


NOf'tOfNtO ©CMCM-H*tj*C 
CO t'- CO CO «ON CNiCOSM 

05 os 05 i^cocoor-occ 

oc oc x> oc jc 00 oc 00 oc oc oc c 

888888 88888 c 

lO o to to O to lOiOiOiOtOi 


S8f 


)XX’rNVO’rO»t005 'ftflC 
- - .r'.I^OCf^^^CM —h CM © © C_ _ _ 

—< _ _ —« _ _h cm CM CM © © O CtCCC M-Tr*r 

xxxxxxm^m^ nn £r tr t: La E; Es 

S8S8888S88SS 888888 

10 to O to to to to IQ to lO to tO O lO to to O to 


Eo„ 

o ^ “ 

O feX 


_? © I - C _ 

G4 M M M 

• OC OC 00 00 00 00 

^QCQQOO 


)SSc 

) © © 1 


00 I'- © © © -*f« 

SS?5E2 $3 
8SSS88 

vO 0 vO vO vO vO 


VO 05 00 CO CM vM CM CO -H* CO CM © 
© © rH 1 ^ CO O I- t 

- ‘ *-v^©O©CC00 


VO »0 »0 »0 vO *0 


©''y©©rHCM00©0C©©00 
O500tOXl'-l-M*-<XC , 3C'l'-» 
r- h«-h»—«CMCM«—<©©© 
x x x x r. x i^- 1 - h- 1 ^ i- 1 ^ 

8 ©©©o©o©©©©© 
©©©ooooo©©© 
©©©©©©©©©©©© 


rH©-HOO©CM 
CM © OC’ © 00 
© © *0 ■'T "vr CO 
f', r>. 

888888 

©©©©©© 


| 

Oh 

© 

a 

1 

xj 


a 

9 

© 


§ 


o 

O 


K © 
© H 

E 3 


r>» r>» t>» r*» vovovovovovo ©©©©coco vovovo»o»ovo 

1 1 1 1 1 1 1 m 1 1 1 1 1 1 1 1 1 Mini 


oooooooocooooooooooooooo t-1» t'- t» 

I I I I I 1 I I I I I I I I I I I I 


c3 


o c L. 

v- a 5 orU 

rC ° x 

o a 


I I I I I I I I I I I I I I I I I I I I I I I 


I I I I I I I I I I I I I I I I I I 


55C* 


£ s ® ON 

gg - ' 

is 

£l 


I © © 3 2 2 2 

CM CM CM CM CM 

I m 1 1 1 1 


© © © © © © 
co ro ro < 

CM CM CM CM CM CM 

I I I I I I 


CM CM CM © © O 
M ^ -H CJ (N CM 
CM CM CM CM CM CM 


oc 00 cr 

,-H O o o 
CM CM CM CM CM CM 


I I I I I I II I 


I I I I I 


S © © © © © 

© © -"tr -h* -rr 

r—< —H r-H rH 

I II I II 


00 OC 00 h rH rH 
CM CM CM CM CM CM 

I I I I I I 


CM CM 00 © © 


»-h CM © t>* rt< © -«t» © rt« rjt © © 


+ I *f + I 4- + + + 4-+ I ++ I + 


+ + + + -M- 


CCO)NO«COvO’I , hX«M 


+++I ++++I+ 


© V rr © V 

rH rH rH rH rH rH 

++++++ 


§2® 
,® fe 3 
r* o.*> 


I I I 


§ cm © —h r^. © 
© CM rf -n* © 

tJ- tJ 1 -^T Tjt 

I I I I I I 


CO © © © 00 

OC 00 CO © © © 
CM CM CM CM CO CM 

I I I I I I 


+ + + 4--I- + + + 4-4-4- + 


»r »r i>. 00 © 
CM CM CM CM CM CO 
CM CM CM CM CM CM 

I I I I I I 


O 

u. 


00 00 © © t» rH CM © CM -h CM O © 00 1 » © © ^ 


CM © © © © © 


I I I I I I I I I I I I I I I I I I I I I I I I 


00 00 © O ^ O CM CM © © © H OOCM^reO©*'- 

r—i rH *H i-H t-H f—( I—* ^ r-4 

I I I I I I II I I I I I I I I I I 


■8 

i 

- 

o 

o 

a 

a 

1 

u 

<x> 

Ph 


a ° 

0*7 H 

o *-ce 

i-4 O _J 
c- 4-5 ^ 

o 8 ' 


00 © © -rj* © CO 

^ Tt< © <0 CO 
• OC 00 00 00 CC 00 

eo©©o©Q© 

©OOOOO 

©©©©©© 


©©©©©© 


co © co 0 r*- cm 
© o © o 

T-H CM CM CO -r ^ 
©©©©©© 
o o O O O O' 
C O O O o o 
©©©©©© 


t- © r-t © 

Xl-'^-t CO 'CO 
OC' 00 GC ■— 1 O O 
00 CO 00 © © © 
©OOOOO 

©ooooo 

©©©©©© 


© CO r-* CO 

C-J N N H H H 

00 00 00 00 oc cc 

888888 

»o © © © © © 


CM -r © © CM CO 

ro — © © 

CM CM CM © © © 

l '- l — © <0 © 

©ooooo 
©ooooo 
©©©©©© 


00 «-h © OC »-« 

rr -»r © © © t'* 
©©©t^t-r^- 
1 — i'-r>-t'* 

888888 

©©©©©© 


w 

o j- x 


CO 1 -t I'- © CO CO 
CM CO C/D O —< l 
© VO ^ t>» © 

• X X X XXX 

’888888 

©©©©©© 


© —• 00 CO CO © 
CM O r—t CM CO rj« 
O O O CM CM CM 

§ 05 05 05 05 05 

88888 

© «o © © © © 


© CM OC © VO 
l> X N CD -H X 
OJ CM CM 2* t-O 

OOOOOO 
©OOOOO 
© © © © © © 


06 »o © © © 

© © © CM 1—t © 
X’ X X O O) o 

©OOOOO 

©©©©©© 


XXOiCXOXXrHOrf© 
tOCtOOHWONrTHHO) 
CO CM O) ' © CM CO CM CM O © © 
X X X X X X 1-- N I'. O 

888888888888 

»o © © © © © © © © *C *0 © 


S CM © CO CO 
■ O CO CO © SJ 
© O © 00 00 OG 

00 oc 00 r- r>- 

888888 

© © © © © © 


C/5 © 
© *- 

r 3 

P-. w 


* CM © CM © © © 

g ©!>.©©©© 


5 c 

< © L 


5 to to «D O tf5 »C CD to l'' to 


© 

a 


o 


Is? 

© at a 

E“ Q.+* 


Qj co co cm -rj- co r>-©-^©©oo t^©©©65^-< cm-tj*- 

-r © © »o © r-3 ^ t-h cm cm cm <6<d© t^-©<o 

0 1 -^ •—< t—« •—> 1—4 CM CM CM CM CM CM CM CM CM Cl CM CM r-t .-h r-< -H 


OlCOI^*-H-rOC©CM©l>.©© 
X 4 rH H M (N N rH C 6 O 


C5 

a 

B 


• © © r- O xr © 
gHHHcinH 


CM X O © © 

CM i-i CM CM* i-I rH 


© © © 00 © © 


© 00 © © 00 00 

H H ci H H H 


*»rr^©o©oo©©oco© >-. 

rHrHCMCM^Hf-IiHCMCMi-5r-^lM* 


»h rr cm -*r 00 

-H CM CM CM rH ^ 


© 00 © © *r cm 
s Tjt ^ © -^ © 


CM •—« © rt* t^» CO 
©©©©©© 


© © ^ 1 —• CM © 
r?* ■’T © »C © 


CO CO © © CO i-4 
©©©©©© 


Xt^©^cOCM©©XCr-^ 

rrTr-^-©©©©©^r©©© 


f>- © © 00 r*. © 
tt © © © co co 


<D 

a cs 


•-H © 

O 4-» 

a 


6 4 0 ■ ■ 

Eaz^t 

§ t-CO 

o a ® 


CMOCOOr-<©H00©CMX 
©©ccoo©oi^rH©r-i-iCM 


«c © © r- O © O 
C) O) 05 O) © © 
CM CM CM CM CM CM 


Si 


CM r—I r-t © © © 

t'- !>• l>» © © © 
CM CM CM CM CM CM 


i-HCMco««f©r- 
X X X N N (>. 
CM CM CM CM CM CM 


© © rr CM CM CM 
rH rH M CM Cl CM 
CO CO CO CO CO CO 


o 

O 


6 

2 w 

-CouX 


ft 5Mn©t'*NC 


O OC © © CM © 

CO* hHHH O ©05 CO CO -4 GO©.—i CM* CO© 

I'- l'- © © © © © L- I- or 1 ^ t^- 

CM CM CM CM CM CM CM CM CM CM CM Cl CM (M CM CM CM CM 


©—HCO©'i'rrCM-n , ©!''-©r'- 
© O © O © O 'T* -^r to © t-O 
CMCOCOCOCOCOCOCOCOCOCOCO 


© © —t 1 - CO © 
CO CO © CO CO CO 


—> 



, CM 

rH . .— 

• • I • 

^ <-* Cl 2 CM CO 

1-< ft T-4 1-i 


•2 ... 

00 x © ©‘ © c 


© • 00 • 
z* * I *c 

OlNNXr 


CM 

. . 1—4 

I ' * I 

1 CM CO • T ' rH rH CM ^ E n M - - 
hhXCCOhhh hhhhhh 


&>>>>> 

OOOOOO 

}zjaS5»fcJ25 


>>>>>> 

OOOOOO 


>.>>>>> 

OOOOOO 


> > > > > 

OOOOOO 


aaaoaaflaaaaa 

03c3cjCvC3c3c3rtc3c3c3c3 


© © © © CD © 
f*H 


s! 

P- ■*-» 


fifififiPP PPPPPP PPPPPP PPPPPP QQQQQQQQQQQQ PPPPPP 


a ■ a 
©35 
a-o a 


©©©©©© © © © © © © 
pppaccQ«« 


©©©©©© 

ttcacacacp 


© © © © vO © 


rr-'TTr^r-'r^r©©©©©© ©©©©©© 

CQCCqC«CQ»0»?Q25fQ» pjcp«m»e 


feO 

.So 

^ 2 ; 

CO 


1-H CM CO ^ © © 1H CM CO 'O © fH CM CO -^ © © *H CM CO ^ © © 


rH CM CO © rH CM •*j* ©© 1^.00 © ^ 00 © 


as 5 

B O » 

•C^ ! 

CS > 

g 0 

« 0=3 

5 g 

T 3 ^ 

a 0 

£ 

5 s 

r0 q 

0 0 

S'® i 


C 3 fu 

X . 


Q © 0 

O Si 

w-§ 1 

gfr * 

0 

2ft 

Ha 

.J 3 

5 ® 

1- 0 

id 

- e • 

qt)Sa 
0 ® 

a-a ►,* 
a — ® 0 

r-» ^ . 


1—H J> 

2 

aag^ 

0^=3 


ov -3 

. 6 

o»-» 

Sgtnd 

5 ^ 


'A 

^ -*« 



•o 

a 

C3 

a 

O 


CQ 

5=1 


fl 

O 5 

BS 

Sti 

W 9 

© o 

as 

o> 

2; 






























































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


161 


X 1-3 

Sg 

S'— rH 
“8 

33 
© © 

H rH 

£g 

N H 

ffg 

X 1-3 

Kg 


X i-3 

88 

05 0* 

£ + 

05 0 

05 0* 

S-H 

05 0* 

05 O 

S-H 

05 © 

05 "H 


05 O 

05 ~H 

h CO 03 00 05 LO 
05 05 O 05 05 O 
X X 05 X X 05 

N003C00050t^05 
XX05XXXXXX 
t"- N N N t'- t- I'— 

NC3NNOHOOOO 

lOONcDONOiOtD 

CO CO CO <0 CO CO CO CO CO 

WOOCOCOOOLONCO 
•-hO*—<00»—(*-hOi— i 
t -n t- n 

SNH005HCCNCO 

N(NW(N(N«C3C3C3 

»-«XX©©©©©© 

MOOC 

888^ 

3N©©rHHjiNN© 

2©©©©©©S§ 

05 05 05 05 05 05 
i - i-- t- t'- 

05 05 05 © 05 05 

050505050505050505 
t'-r>- r- t- I s - r- 
050505050505050505 

05 05 05 05 05 05 05 05 05 
t - i'-1 - i'- i— t'- i'- r— t ^ 

05 05 05 05 05 05 05 05 05 

05 05 05 05 05 05 05 05 05 
r- r- t-- t- I-- r- t'- i- t- 
05 05 05 05 05 05 05 05 05 

05 05 05 05 05 05 05 05 05 

r-- r- r-- r- r- 

05 05 G5 05 05 05 05 05 05 

050505050505050505 
r- i- +- i- r- 
05 05 05 05 05 05 05 05 05 

05 05 05 05 05 05 05 05 05 05 05 05 

05 05 05 05 05 05 05 05 05 05 05 05 


. 5007771 
. 5007765 
. 5007744 
. 5007566 
. 5007564 
. 5007548 

. 5008039 
. 5008039 
. 5008024 
. 5007861 
. 5007852 
. 5007844 
. 5007854 
. 5007850 
.5007844 

. 5008180 
. 5008168 
. 5008144 

. 5008358 

. 5008362 

. 5008336 

. 5008362 

. 5008364 

. 5008342 

. 5008228 

. 5008240 

. 5008228 

. 5008057 

. 5008052 

. 5008030 

. 5008035 

. 5008054 

. 5008032 

. 5008003 

. 5008004 

. 5007993 

. 5008194 

.5008186 

.5008180 

.5008201 

.5008192 

.5008192 

. 5008233 

. 5008228 

.5008213 

. 5008024 

.5008030 

.5008006 

. 5008032 

. 5008030 

. 500S006 

. 5008319 

. 5008327 

.5008313 

. 5008516 

. 5008510 

. 5008504 

.5008516 

.5008514 

. 5008505 

. 5008509 

. 500S510 

. 5008493 

iCMiOHWOO 
O O IO CD O lO 
I'* l- N iO iO >0 
i- t> i'-1-- 

888888 
O iO >c >o iO >o 

. 5008030 
. 5008034 
. 5008038 
. 5007854 
. 5007850 
. 5007852 
. 5007843 
. 5007847 
. 5007856 

. 5008170 
. 5008166 
. 5008156 
. 5008351 
. 5008361 
. 5008348 
. 5008351 
. 5008363 

. 5008355 

. 5008220 

. 5008240 

. 5008235 

. 5008047 

. 5008049 

. 5008041 

. 5008025 

. 5008052 

. 5008042 

.5007995 

.5008002 

.5008004 

.6008186 

. 5008184 

. 5008189 

.5008192 

.5008194 

. 5008198 

. 5008222 

. 5008222 

.500S222 

.5008017 

. 5008028 

.500S018 

.500S027 

.5008028 

. 5008017 

. 5008314 

. 5008322 

.5008324 

.500850S 

.5008509 

.5008518 

. 5008510 

.5008511 

.5008513 

.5008504 

.5008508 i 

.5008506 ! 

.5007778 
.5007767 
.5007734 
. 5007572 
. 5007565 
. 5007539 

. 5008048 
. 5008044 
. 5008010 
. 5007868 
. 5007855 
. 5007835 
. 5007865 
. 5007853 
. 5007831 

. 5008189 
. 5008169 
. 5008133 
. 5008365 
. 5008363 
. 5008325 
. 5008373 
. 5008366 
. 5008330 

. 5008235 
. 5008240 
. 5008220 

. 5008067 

. 5008054 

. 5008020 

. 5008045 

. 5008055 

. 500S023 

.5008011 

. 5008005 

.5007982 

.5008201 

.5008187 

.5008170 

.5008210 

.5008190 

.5008185 

.5008244 

.5008234 

. 5008204 

.5008031 

.5008032 

. 5007994 

.5008038 

. 5008033 

. 5007994 

. 5008324 

. 5008332 

.5008302 

.5008525 

.5008512 

. 5008491 

.5008522 

.5008516 

.5008497 

.5008514 

.5008512 

.5008480 

f- t-1«- 

i 1 1 1 11 

xxxxxxxxx 

1 II 1 1 1 1 1 1 

XXXXXXXXX 

1 1 1 1 1 1 1 1 1 

rH rH rH rH rH rH rH rH rH 
rH rH rH rH rH rH rH rH rH 

1 1 1 I 1 1 1 1 1 

ooooooooo 

rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 

i i i i i i i i i i i i 

CO CO CO © © © 
C3 03 N O O © 

r—4 *—( rH rH i—4 rH 

1 1 1 1 1 1 

COXXC3CIM»OiCiO 
CC O C N I > O CD 

777777777 

©©©©©©©©© 

rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

t^r^r^NNN©©© 

©©©XXX©©© 

777777777 

X00 00©®iO3QO)C5 

OOO*—IHHHHH 
rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

XXX©©©©©© 

iOiOiONNt»COO!0 

777777777 

COCOOrrr*. Tf <CNCN<M<M<NCN 

XXX05050103C505C505D 

HHHHHHHHHrHHH 

I I 1 1 1 1 1 I 1 1 1 1 

CO CO CO 03 03 03 
CO CO CO X X X 

rH r—1 rH rH rH rH 

1 1 1 1 1 1 

NNN©©©©©© 
NNNNNNNNN 
NNNNNNNNN 

1 1 1 1 II 1 1 1 

hhhcOCCcOWNN 

NNNOOOhhh 

(NDIWWNCKNMW 

1 1 1 1 II 1 1 1 

CDCDCOWNCIOOO 

hhhNNWOOO 

NNNNNNNNN 

1 1 1 1 1 1 1 1 1 

XXXXXXrHrHrH 

iDiO>0*OiflOXCOX 

rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 II 1 

I0i0i0i0*0»00c00 
05 05 05000000 
rHrHrHCNCNCNCNCNCN 

1 1 1 1 1 1 1 1 1 

CNNCNO©©©©©©©© 

XXXM-tt^XXXXXX 

<MCNCNCN<MCNCNCNCN<MCNCN 

1 1 1 1 1 1 1 1 1 1 1 1 

1-3 TT CO C3 ^ TJ1 

rH rH 

^CDONCDiO^WW 

XXt-XXNrH©© 
rH rH rH rH rH 

lOCOXXNiOhOh 

CO»CNNNCOHiCX 

rH rH rH 

OMCONCOW5tjiM 

rH rH 

•**XCNCN-^iOt>.X©»-fCNX 

rH rH rH rH rH rH rH 

+ 1 + 1 1 1 

+++++++++ 

+++++++++ 

+++++++ 1 

1 1 1 + 1 I 1 1 1 

+++++++++ 

+ + +1 1 II 1 1 1 1 1 

CO 05 03 H 1-4 X 
N •O 05 X N 

lOiOHCONiCNNN 
*h h C3 C3 X'T ir'T’T 

rH rH rH rH rH rH rH rH rH 

XNW^OCClNOiO 

hhhMiOOOGMD 

11+++++++ 

Xr-ixr-Tjix<Nxx 
XHX'CNrHONCO 
rH rH 

NijiOO^TfiCiCrfM 

NNOtCtCCNHO 

<N<MCS<M<MCNCMCNCM 

1 -HOOOrHOXXCN 

OOJCOHjiHj'Tr^X 

© © X © X © CO X 

H<M<NXXXCNCN<NCNCNCN 
CNCNCNCNCNCN<NCN<N<NCNCN 

1 II 1 II 1 1 1 




1 II 1 1 1 1 1 1 1 I I 

NOMNNCO 

rH rH rH rH 

1 1 1 1 1 1 

NNNOOOOOOOOiO 

rH rH rH rH 

1 1 1 1 1 1 1 1 1 

rrXOXNrrX©© 

rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

NOOWNNOOOJN 

1 1 1 1 1 1 1 1 1 

M>ONHNXHOiX 

rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

X©©©rJJ©rH©© 

1 1 1 1 1 1 1 1 1 

NOCNNHOOU5MWHCNU5 

H H H rH rH rH H 

1 1 1 1 1 1 1 1 1 1 1 1 

,5007887 
5007881 
, 5007843 
, 5007596 
, 5007564 
, 5007509 

.5008321 
. 5008326 
.5008341 
. 5008163 
. 5008169 
. 5008180 
. 5008162 
. 5008168 
. 5008177 

. 5008364 
. 5008358 
. 5008321 
.5008472 
. 5008470 
. 5008122 
.5008416 
. 5008452 
. 5008451 

. 5008262 
. 5008312 
. 5008334 
. 5008182 
.5008218 
. 5008224 
. 500S121 
. 5008168 
. 5008167 

.5007852 
. 5007856 
. 5007873 
. 5008069 
. 5008083 
. 5008102 
. 5008118 
.5008133 
. 5008150 

. 5008486 
. 5008479 
. 5008457 
. 5008239 
.5008262 
. 5008247 
. 500S257 
.5008247 

. 5008202 

.5008719 

. 5008738 

.5008745 

. 5008953 

. 5008903 

. 5008962 

. 5008947 

. 5008957 

. 5008960 

. 5008949 

. 5008955 

.5008946 


HiOCS't'^N 
•rf N COCCCJH 
Ol o cc o lO Id 
r- d- r- r- 

gggggg 

lOOiCOiOO 


CO*OClONCD’9 , 'tC3 

OON«C3*htt^h 

XXXNNNNNN 

y. s / x x x x x x 

888888888 
O lO O lO lO lO lO ‘O lO 


NiCCSCOCOOOiOC CDHCO^COONNO 
CO h O Cl lO 03 h X N©©Hi©'T't'-©l>* 
’rnWiOOT-riO'T' CO CO CO M C>1 M h M -h 

x x c/f x oo go co oo oo xxxxxxxxx 

888888888 888888888 

o lO iO lO »0 »C lO O IO LO »0 >0 *0 >0 1C »0 lO >o 


COTf COOOONOOHC5 __ - 

•H O 05 H (N Hrf TJ1 TfMNNOTrOX 
OOCCHHHHHH © © rr N N N X N N 

. . . - 00 X X X X X X X' X 

QOOOOOOOO 


_ . . 3 00 0) 

NNNOOOJO 
5©©- 


X 05 05 IO 
- _ _ 05 05 05 05 

X X 05 X X X X 


Cl N N Id N CO 
© © © © © 

©t>»X©X©©rHrH 

©©©©©©©©© 

lOUOtCODOHdCO 

©©© 131 ^ 31 ©©©© 

^-©©^©t^NXH 

tOiO©»OiOtO©©© 

©t-©©^XXt^rH 

©©©©©©t-r^x 

X<CCf)r}i<ON!»©0 

©©©©©©©©© 

©OhN©OCNX©<ONCO 

© © © N X © 

x x r- x x t" 

lOtOOCNXtO©©© 

t^.t'-05©CN'tf'''*'>3i'3’ 

OOOXOOOCN© 

CO”TNhXC1XXM- 

©iO©tONX©tO© 

t^x©©’«r©XCN© 

X©QCNXXCNX© 

X-*r©©rtX©Xrt 

O »0 N © X © © © © 
VHt?<DC5 05HDO 

N©©CN00O©©00©©CN 

CN-n’rr©©©r»iHjicOXXX 

H -r X CN H O 

H rH H H H rH 

t^t^r^xxxxxod 

H H H H H H H H H 

tOtOH-rXCNCNXX 

rH rH H H rH rH rH rH rH 

HCNNXHHC'JXX 

rH rH rH rH rH rH rH rH rH 

xooxoo©©©©© 

rH 

1^1^©©©©©©© 

HHHHHHHHH 

OOOOOOOQOOOO 

NNNNNNNNNNNN 

tO © X 05 CM CN 

05C5r-05C0Xf-XX 

xr-©t^©Tjir>-t'-x 

tO©©t 0 ^f©X©© 

CNCNCN©©X©Tji© 

©X^©rH05©t>»rH 

Xa© 0 ©NHNXNt'U< 

hhNhhN 

HHCNHHrHrHHH 

CNHCN HCNCNHHH 

rHrHN 1 -HrHrHrHrHrH 

CNrHCNrHrHCN»Hi-Hi-H 

HHNHCiH rH rH N 

rH rH CN H H rH rH rH CN rH rH rH 

cm r- © © © x 

NNCIOOJDNXN 

©t--©t>xx©xx 

MMOCOiflOHCOCN 

NOiJ<COONCNt}<0 

X©XX©©Tt<©C5 

©XH© 00 <C©^NO)CNO 

© © © -r © 

tO tO © © *^i ^3* 

cD'^ , to ,, <T , ©©' T t , 'Tr© 


©rji©©©©©©© 

Hairfi©x©^©©Tr 

tji©©^©^xc 6 ©©©x 

r- H CD CN © H 
H 1 ' CN <D O -r 

wOCO^XifCNDOOf 

Dl-CNl-iOHNiOCN 

©XiO©XtOtOX^ 

HtO©©©XtOCNX 

X©t^©N©©^-© 

ONTrONtOXUOO 

O'tCO^COOOCDX’f 

©NOXNOVXN 

rH©©N©'^ , ©'»+© 

rHXrH05©©N©X 

MOCOCNCNOOCN©NNN^f 

N©Xl''-Tj'Tt!©©lOOO©© 

N N oi d H CO 
H H H CM X X 
XXXXXX 

ggggsssss 

xxxxxxxxx 

C5 C5 © lO to © © 

Oi05©C5 05 05 05 05 05 
CNCNX<NCN<NCN<NCN 

80000 S 00 S 

xxxxxxxxx 

o 6 xoo©©©xr^*t- 

hhhhOOOOO 

XXXXXXXXX 

©©©xxxxx© 

©©©©©©©©© 

CNNNXXXXXX 

^-©©©©05050505050505 

O 0 CCO 0 NNNNl>.t".h.NN 

NNNNNNNNNNNN 

CN tO X X CN X 
X © H 05 t— O 

OOCNNOOhNOUO 

HXHCNXxr-»HC5 

OONCNCNXOOH 

X©XCNr-CNt^HH 

<OOCON<OHNO<D 

t'-»ONXO©^rXrH 

XO©©X©CNO© 

tTOOhhX©X!DX 

OOCO©OC©©CN©00 

©©■rrTt 1 ©©©l-Ht>. 

©H©HQOO©©ir<DXN 

XX©X©00XN00XX© 

id <d 00 N nj co 

H H H CN N CO 
XXXXXX 

X’ X © H H H* CO H* H 
©©©©©OOOO 
CNCNCNXXXXXX 

CD N ci CO CO <D +- d LO 
© © © © © © © © © 
<MN<MNNNNN<M 

©<©©XXX©tO© 

©©©ooooo© 

XC4NXXXXXX 

OONCOCOOOSNN 

rHrHrHOCOOO© 

XXXXXXXXX 

WX'ONNXHN'C 

05©©0©0©©© 

NO^CNXXXXXX 

HHHr4t^ajp6coo6o6o6c» 

NNNNNNNNNNNN 

!© ! !© ! 
,CN . .CN . 

nr -+ to to to CD 

CN CN CN CN CN CN 

: : : :h : :<n : 

, © • . rH • • H • 

. H • • 1 • • 1 ' 

. IO©Ohhh<M 

©©rHrHrHrHrHrHrH 

: \ ; x ; : © ; 

i rH • . rH i iH • 

©cir^t^rixodci© 

rH rH rH rH rH H rH rH rH 

; © *. : ; 

. CN . . N . .X . 

toJocd©’©^’©©© 

NNNNNNNNX 

!© j I joo j 

© Jo © © Jo r-’ r-’ rl od 

i” : • is ; 

NCNcOXCOtjJ^h^© 

HHHHHHHHH 

1 i 1 • i • i , « • ( t 

!x ! ’ mi • •© • *<o * 

:7 : 1a • • •<? • 

rti^+©to»Oco 

NCMNNCNnnCNcNNCNn 

D 3) $ O Q O 
ft, (i, p p p P 

C3c<3c3a3c3o3ct3o3c3 

^rrrircircTri: 

c3o3c3g3?3c<3c3c3c3 

sassssssa 

cacSoScocScScaoScS 

sssssssss 

aaQ,ap,Pia.PiOi 

MV4lHlHt-il-itH(HtH 

HHHHHHHHHHHH 

OfifiOfifi 

PPPPPPPPP 

ppppppppp 

ppppppppp 

PRPPRRPRfl 

PPPPPPPPP 

pppppppppppp 

©©©©©© 

©©©©©©©©© 

© © © tO © © © © tO 

to©©©©©©©© 

mpqpQWpqfqMpqpq 

©©©©©©©©© 

©©©©©©©©© 

pqpqpqpqpqpq«m« 

©©©©©©©©©©©© 

pqwWpqpqpqpqmp;pqpqpQ 

H CN X "if © CO 

HCNX-'J*tO©t'-X© 

HNXrr©©r-X© 

rHCNX^tO©t^-X© 

rHCNXrf©©t^X© 

iHCNX'^tOOt'-X© 

HNX’**©©t>-00©©rHN 
rH rH rH 


d 

> 

csT©3 

%% 

f <2 

a . 
go 

Si 

^joPh 

fp 

o 

&T| 

M 

Si 

So. 

iston-Sa- 
John D. 

si 

as o 

S • 
■So 

p, o 

5 i 

p 

& O 

O • 

“1 


H a 
.■§ 

w p 

=1 

o*-> 

oo >-> 

HJ 1 

6 ^!”® 

05 r 

. 

6?1 "S 

d-9 

© O 

?H >“> 

od 

rH *“5 
© * 

6^4 ® 

'"as 

o 2 o< 

N r. 
lO ■ 

'"o 

oZ‘ 




£ 


5C 


59387°—17-11 





















































































Pendulum observations and reductions —Continued. 


162 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


s 

© 


3 

s 


Oi rH 
©8 
O © 

&-H 


© <5 


04 —< 
£8 
Ci O 

© "H 


OOC-iOOCMOOiO 

'*•0000005000 

5>.© 05 05 05 05 05 05 05 05 
P- l •• N P— N N N P- P« 
^ 05 05 05050505050505 


rf^T'rrCirMC'jNlNWiHMiO 

hhhOhhOhhhhh 

t'»Nt^P»NP»l'*t^P-I'*P*N 

05 05 05 05 05 05 05 05 05 05 05 05 
i- r- i^ i— 

05 05 05 05 05 05 05 05 05 05 05 05 


cocoooi-tco'*rt>-ocic'j 

rHHHrH»HrH,-H©©rH 

t'-1'-1-» t"* t'- r*- p" 

05 05 05 05 05 C5 05 C5 05 
r- t>. r-- p- p- p~ 
050505 05 005050505 


T3 

c- 

-+-> 

1 

H 

O 

© 


© 

Ph 


© 

© 

C3 


G 

© 

> 

© 


o 

O 


Mean 

s. 

0.5008398 

. 5008400 

.5008392 

.5008213 

.5008206 

.5008192 

.5008200 

. 5008200 

. 50081S6 

.5008036 

.5008036 

. 5008036 

. 5008049 

. 5008045 

. 5008040 

. 5008242 

. 5008230 

.5008227 

. 5008231 

. 5008229 

. 500S222 

.5008038 

.5008032 

.5008026 

.5008232 

.5008226 

. 5008224 

. 5008242 

. .5008240 

.500S230 

.5008302 

.5008286 

.5008286 

. 5008295 

. 5008286 

. 5008282 

. 5007220 

.5007206 

. 5007194 

. 5007022 

. 5007008 

.5007008 

Chronom¬ 
eter No. 

1S41 

s. 

0.5008392 

.5008397 

. 5008403 

. 5008209 

.5008201 

. 5008206 

. 5008195 

. 5008197 

. 5008197 

. 5008034 

.500S030 

.5008043 

. 500,8046 

.5008042 

.5008047 

.5008237 

. .5008229 

.5008239 

. 5008223 

.5008226 

.5008235 

. 5008034 

.5008027 

.5008037 

.5008223 

. 5008223 

.5008238 

.5008236 

.5008234 

.5008240 

. 5008293 

. 5008284 

.5008297 

. 5008288 

. 5008285 

. 5008292 

. 5007212 

.5007205 

.5007205 

.5007011 

.5007007 

.5007017 

• 

r-> • 

G C ^ 

2*8 

£fe® 

r* © 

s. 

0-5008403 
. 5008402 

. 5008381 

. 5008217 

. 5008212 

.5008178 

.5008205 

.5008204 

.5008175 

.500S039 

.5008041 

. 5008030 

. 5008052 

. 5008048 

. 5008032 

. 5008246 

.5008231 

.5008215 

.5008239 

.5008232 

. 5008208 

.5008042 

.5008037 

.5008015 

. 5008240 

.5008230 

.5008209 

.5008249 

.5008246 

.5008221 

ON'TC'lNHNCCM'rXOO 
X r - o X 1- 04 p X X O O'. 

X 04 04 X 04 04 04 04 © O CT. 

X X X X X X t - P- ! - t'- P'* CC 

ccSo88S88co8 

iO *o tO to LC 1 © to tO »c to »c »o 


Flex¬ 

ure 

xxxxxxxxx 

1 1 1 1 1 1 1 1 1 

oocooooooooo 

1 1 1 1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 

r«H *H ^H *—1 r-H «-H r-* H rH ( rH rH 
H H rH r - rH t~* rH rH *-H r—> rH i—« 

1 1 1 1 1 1 II 1 1 1 1 

1 

Chro¬ 

nom¬ 

eter 

No. 

1S41 

C3©i OlCOCOCOHHH 

t^t^t^t^P^P^XXX 

777777777 

N p. p. rf rf Tp N p» p. © © © 
X X X CT> O 05 X 1 X X Ci o> O 

777777777777 

NNN®©©0OCC'X 

ccocoo©©© 

©4<NC4C'4<©4<N-H.— r- 
1 1 1 1 1 1 1 1 1 

OOOtOlOtOnHrHrHXXX 
X X X CO cc CO P- p- CO CO cc 

777777777777 

pH 

Chro¬ 

nom¬ 

eter 

No. 

1823 

iCiOtCWMMNNN 
NMC4 (MiN(Mhhh 
C4 <>4 <M 04 <M 04 C-4 <M C4 

1 1 1 1 1 1 1 II 

HHHOOJOHHHLClCtO 

000©CJ®00Chhh 

C'4C4<©4t-HrHrH04C'K©4©4'©404 

II 1 II 1 1 1 1 1 1 1 

NNNOOOOCCCC 
04 O! 04 04 04 04 O O O 
04 04 04 040104040404 

1 1 1 1 1 1 1 1 1 

»©. to 1C 1C; 1C it N N N CC X CO 

0404040J 04 04 04 04 04 04 04 04 

1 1 1 1 1 1 1 1 1 1 1 1 


C/5 05 

© b 
P* w 


TtuiPcacC' 


n i + ii + i i i i i +1 i +1 i i i t* mi + 


i i 


•vCNOWCthNCNO^ 

4-4-4- I 14-114- I 


£ ob £ 




CO CC lO 00 rH r-< 

CS rr CO co 00 00 
04 04 <M 04 04 04 04 

I I I Mil 


OOCOCOt'~GOi-H05P-»OC'4C5CO 
CO CO CO O l 04 CO t- 05 O 04 

-HHMOC4(Nr-rHCJlNOW 

I I II I I I II I I I 


»0 1—l CO C4 t© P* P'* X P'- 
00 GO 05 c C —• 04 CO 
r-HHrtlNfNlNCUN 

I I I I I I I I I 


I ' CO C4 050T C<, CO PO N "T 
CC-HOI-or. OCMCO- «ft CO CO 
70 00000404040404040404 04 

I I II I II I I I I I 


t00404tOt'-tOtOt'-04 


O5O4O4GO5CCl>-0CO5 


3 05 05 - 


■ r- 04 O CO r^. 05 CO O 


I I I I I I II I I I I I I I I I I I I I I 1 1 1 I II I I M I I I I I I I I I I 


$ 

1 

b 

t— 

O 

© 

O 

i 


So 

C *- X 

5 ^ 

S * 


t^COO5iOCOO500U0CO 
X tP OO Tp © X UO 00 o 

CCOOMCCCCCCCON 

•xxxxxxxxx 

«goooooogg 

tOtOtOtOtOtOtOtOtO 


't'HHTf'tCH(ZlO l OlCCO 
O CO CO 1-- OC -H 04 t I - t© cc 05 
Tf n 1 T V 1 LO CO C cc c cc O 
GO CO 00 X X GO OC CC CC 00 X CC 

§ooooScSScSS 

lO »o to »o to t© t© I© to l© t© t© 


*-h -T CC CO 05 05 O 

-p lO t© Tp -*V P>» cc 
-r rr -r O C C C 

00 00 CC GO OC GO 00 

ggggggg 

lO «C >C O u3 lO >0 


05 O 
CO 

CO CO 

II 


-5 OC' O IG N 05 S p- cc N 
X P- t- P- P- CO CO COP-rr T 
X f/j X 00 X OC N N 1- N N N 

§88888888888 

t© »o t© i© t© •© t© o t© >© t© »© 


G o 

2 fe* 

s® 


05 05 ^0040004 04 

x oo go r- t- i- p- t- 

• 00 00 00 CO QP 00 QO GO QO 

^QOOOOOOOO 


o 


CCCOOJiCtOCOP'TfCCOlO 
04i0C0C005O^Oc0Cr. C5GO 

-rrp-frM*’*r»ccococococOco 

XXXXXXXXXXX CO 

888888888888 

lO »c IG 1C 1-G to »C 'C t© t© 'C to 


OrfC'tP.r-i —I o 

C CC ‘C N C C C O 

*• rr «> 'C C C I' N CC 

xxxxxxxxx 

8888 S88SS 

*o *o •. »o >c »© »o »o lO 


t ^SPo! r ^^^ocor-^p^05co 
CD04 ChCO®SOhOO 
CC 00 CC CC 00 CC O CO O to to to 
xxx x x x r- p- p- 

gggggggggggg 

iO »o to *o to *o «o to »o *o »o to 


£;" S 


C4NCO^ WCOCCOO 
OONCCNCCCNX) 


OON'rr>OC5CONHN«(}-OJ 

Tp to tc co r o cc c n i-o cc o 


Oh to 


© 

b 

c3 

Final 

gj *H ’O cO H CO *C H P4 X 
^HHOlHHOinHOl 

hC4N©H00O4XO5P-00h 

hhN04hhhhNhhC4 

iOt>.COXXXTP©»-4 

hh04hhC4 01h04 

OOONMXOhNiOOXOO 

Nhh(Nh(N04hhhhh 

•*H 

o 

Ini¬ 

tial 

^ X tP 04 hh »0 O H O 04 

§ tp co to* tp tp cd to to 

lOTp^xt^-OSTpoOOXO 

TpcdcccoTP^pcccct^cdtdtd 

04©XOJ©COXCOtO 

tdccidtdtdtdcctoTP 

HP.XONL-0O©04P.HV 

to-n-^io-ptotdTP-PTpcdtd 


9 g 2 
® Sd 
H Q-+- 5 


O «-H o O O rH »-H H hH —< XX 

04040404 04 04 04 04(04 rH 


05 -r TP lO' 04 P- X' O 04 CO 

05 C5 05 C O © 
04 04 04 


rH CO CO to 05 05 rH rp CO 

05 05 ^05^05000 


t0»0 04 04i0XOXOTPOX 
o to 04 »0 X TP to X rH 00 CO 

cooi(N~^-iddc^rH^ 
04 04 04 04 04 04C40404040404 


© 

©~ 
G ? 
© > 
©3 *■« 
•in © 
O 4J 

a 

o 

O 


1 £ O f-4 

^ O b* 

O © pH 


HCWNP-'PiOOiO 

TP04C0C0050404XCD 

Wcccococsoocjocsoor^ 
x x x x x x x x x 

04 04 04040404040404 


r^p-p-toto-roo5x©303X 
05 05 05 05 05 05 05 CO CO X XX 
04040404040404040404 04 04 


CO CO CO 05 05 00 X X P'* 


OX'P i tPOOXh 04040I s - 
h05 05hP4u3ih04cChi005 

-P-^'tpcOCOtOCOOOP^COtC^ 
2S $0 XXX X 0^ 04 X X X 

C4040404 04 04CGCOCOWMW 


6 

O C © 

»-< 4 J 


05 05 CO CO I s * H 04 Tp O 
to to to X o CO 05 04 

fl,;,,H »PNP*P^P*P‘OP* 
X Xoo x XX X XX 
040404040404040404 


MHOhXVP-OC 


t h. co to tp ^p 05 05 05 x 

05 05 05 04 05 05 X X X X 
04 04 04 04 04 04 - 


X 

_X 

04 04 04 04 04 04 


»0t0CCXX03t'-P^X 
05 05 03XXXXXX 
040404040404040404 


X’*PX04C5XOXXXC004 

pNiCOTj’tOCOHt.COT'N 


CO 

Q 


• 

^ C3 

to iS . 

r-t O I • • I f*| « 

>1 >i P>1 >> k >5 >1 

rt Cfl c3 03 ^ C3 


.04 


■ . . TP . .04 . .X . 

I H • I H I I H • I H • 

O incoci TP r-M 04 04 <04 cc 

»—< r—< ^-( »—( »—( *—( »-H i—H t—i »—( 

rtc3c3c3c3c3o3c3c3o3c3c3 


Q./^c3©c3c3c8c3c3 rtc3c3c3c3c3c3c3c303(33c3 


• 8 J .*04 1 ! 04 

^^88^04040404 
c3c3c3c3^^o3o3rt 


. 05 . 

« rH • 
X o£) ©5 


• 3 


04 

DPP3P3Sp3p9p 


O.S 


QfiQfiflOflfifi flQfiflflOOfifiOQfl afiOfififiOOQ fifiOfiOQfififififlq 


SiS 

c.'oH 


CuD 

.9 6 

CO 


© 

i 

© 

I 

TP 

G 

© 

G 

O 

© 

CO 


tOtOiOCOCOCOCOCOCO 

pqpppQttpqpqpqpqp 


COCOXcOCOcOtOiOLOiOtOtO 

pqpQWpqweQCQ«pqpq«w 


COCOCOtOtOtOtOtOtO 

«pqp3pqpqpqpqp;pq 


rp Tp H" rp Tp -rp lO »C tO CO C© CO 

pqm«pqwm«»pq pqpqm 


HNCO^tOCCNCOO H04WOH04^tOONXC5 H 04 X Tp t© CO t>. X 05 H04C0O H04p- iOCDNXO 


i 

sp, 

C3 

r© 

■3 fl 
t»23 

!i 

•sf 

.'O' 

ft s 

® O 

o 

& 

s & 

m o 
‘SPh 


hk t 

•* 

« . 

°[ | 

K J= 

toed 

Op,© 


G p- 3 

-It 

oHPh 

rH G l* 

® ° 

U3 fl 

^-g 

Ot-9 

3 1 

C0 O 

'A 

dZ fcei 


£ 


© 

>>* 













































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


1G3 


O 1 -c 

38 

iC 1—1 

GO O 

CD O 

38 

1 "^ 

58 

*0 

rH O 

*0 O 

CP ^H 

00 1 -H 

CO © 

-*i © 

O 0 

00 _u 

C5 ** 

d d 

CO 11 

Ci 1 * 

8 ° 

05 •* 

d d 

GO ii 

o> <* 

do 

00 4-1 

CP *> 

©d 

I-H 

© d 

00 11 

Oi Ml 

iOOtPNIMtPiOH-P 

-P *C i-O tp O *0 ■fl* *0 *0 
10 * 0 * 0 * 0 * 0 * 0 * 0 * 0*0 

iOCOr}4U5^fieOOOO>CP 

GCGODSCOOOOll^r^CO 

cDcDcDcdcOCDcDcDcD 

CO Tp 00 (30 H *0 tp m O ® d Tp 
OOCOCOIMCOCODICOCOC^COCO 

*0 *0 *0 *0 *0 *0 *0 *C ‘O 10 10 *0 

DX*OtPDtpO><CC4 

CDMOOCCOOCDN 

hhMhhMhhh 

10 * 01010 * 010 * 0 * 0*0 

CP©-HcDCCTrr^cDGO 

op©ccpcp©cpCpcp 

r>-oocot^r^oct^r^i"- 

*OCCOOOO©t^*DOO»-» 

cccceccO'TrTjicoccTT' 

irTrTpTr'Tj’TfiTj'TjiTy 

ooooodooo 

00 CO 00 CO CO 00 CO OC '30 
05 05 05 05 05 05 05 05 05 

ddddddddd 

00 X> CC 00 CO 00 00 00 GO 
003DC>DC35050505 

cooooooooodo 

CCOOCCOOGCGOGC-OOGOGOOC-CO 
O D C. O O O; D D D C D D 

ddodddddo 
01 OC' cc oc cc (s„ zr cc 00 
O OP 07 Oi Oi DJ os op Op 

oooooodod 
GG 0 : OC X zr cc cc oc 00 
OPOPOPOPOPCPOPCPOP 

coccoococ 

5C (X. X X S X CC GC cc 
©©©©©©©©© 

ddddddddd 

CC GC CC GC X X x X CC 
©©©©©©©© © 

.5007184 
.5007170 
. 5007159 
.5006094 
. 5006082 
. 5006078 
.5005908 
.5005892 
.5005884 

. 5005743 
.5005747 
. 5005721 
. 5005549 
. 5005554 
. 5005530 
. 5005567 
. 5005565 
. 5005548 

. 5007214 

. 5007212 

. 5007202 

. 5006142 

. 5006134 

. 5006126 

.5005962 

.5005942 

.5005932 

. 5005948 

.5005940 

.5005935 

.5007376 

.5007379 

.5007362 

.5006282 

.5006294 

.5006282 

.5006102 

.5006108 

.5006094 

.5007258 

.5007265 

.5007246 

.5006188 

.5006174 

.5006162 

.5005996 

.5005982 

.5005978 

.5006534 

.5006531 

.5006530 

.5005458 

.5005454 

.5005439 

.5005263 

.5005267 

.5005261 

.5007462 

.5007468 

.5007455 

.5006372 

.5006367 

.5006350 

.5006189 

.5006179 

.5006174 

.5007177 
.5007168 
.5007173 
.5006086 
.5006083 
.5006090 
. 5005902 
. 5005890 
. 5005891 

. 5005739 
. 5005746 
. 5005727 
.5005547 
. 5005552 
. 5005534 
.5005565 
.5005562 
.5005558 

.5007211 
. 5007207 
.5007211 
.5006137 

. 5006132 

.5006135 

. 5005960 

.5005945 

.5005942 

.5005941 

.5005935 

. 5005937 

.5007369 

.5007378 

.5007373 

. 5006275 

.5006288 

.5006294 

.5006100 

.5006103 

.5006103 

.5007248 

.5007268 

.5007253 

.5006182 

.5006172 

.5006170 

.5005988 

.5005982 

.5005987 

.5006529 

.5006529 

.5006539 

.5005454 

.5005450 

.5005446 

.5005257 

.5005266 

.5005272 

.5007461 

.5007464 

.5007458 

.5006366 

.5006364 

.5006362 

.5006184 

.5006176 

.5006182 

.5007191 
. 5007172 
.5007145 
.5006102 
.5006082 
. 5006067 
. 5005914 
.5005895 
. 5005876 

.5005747 
. 5005748 
.5005715 
. 5005551 
.5005557 
. 5005526 
.5005569 
. 5005568 
.5005537 

.5007218 
.5007217 
.5007193 
.5006146 
. 5006136 
.5006116 
.5005964 
.5005940 
.5005922 
.5005956 

.5005944 

.5005933 

.5007383 

.5007380 

.5007352 

.5006288 

.5006299 

.5006270 

.5006104 

.5006113 

.5006086 

.5007269 

.5007262 

.5007239 

.5006195 

.5006175 

.5006153 

.5006003 

.5005982 

.5005968 

.5006539 

.5006533 

.5006522 

.5005461 

.5005457 

.5005431 

.5005270 

.5005269 

.5005250 

.5007462 

.5007471 

.5007452 

.5006378 

.5006370 

.5006339 

.5006194 

.5006182 

.5006165 

1 1 1 1 1 1 1 1 1 

CD CD CD CD CD CD CD CD CD 

1 I 1 1 1 1 1 1 1 

cocccococowcocococceoco 

1 1 II 1 1 1 1 1 1 1 1 

GPGPOPOGPGPOPOPGP 

1 1 1 1 1 1 1 1 1 

C^CMC^<MCM<MCN<MCN 

1 -H 1 -H 1-H r—« f-H 1 -H »-H 1 -H ^H 

1 1 1 1 1 1 1 1 1 

OPOPCPGPOP©GPOPOP 

1 1 1 1 1 1 1 1 1 

coooocococooococoo 

1 1 1 1 1 1 1 1 1 

00 00 00 00 CO 00 r-l M H 
COCOOCtOOlrNN 

•“H *—« rH i-H i-H i-H f-H i-H r-H 

1 1 1 1 1 1 1 1 1 

HHHHHHOOOOOO 

CCCCOOOGCOCOOiOiO 

777777777 

COCOCONt''I'- , 1 1 TP«pTrTPTp 

CCCDCDCDCDCDNNI^NNN 

777777777777 

r^r^i-osopoicocoeo 

Cl Cl M CC CO CC' tp tp 

777777777 

DDD’pTpTpOOO 

CSCSClTPTpTpiO*0*0 

777777777 

t'»t''»t'-0C 00 0C*C*O»D 
eocccccccceococccc 

777777777 

T?iH?iTjir>-rH.r^ooocoo 
CO COCCtP'tT'hPCMCICM 

777777777 

HHHOOOOOO^PTfTp 

cmcmcmcmcmcmcmcmcm 

1 1 1 1 1 1 1 1 1 

NNNNNNHHH 

c353cq55S5c3888 

1 1 I 1 1 1 1 i I 

HHHTPTpirDDDODD 

COCOCCCCCOCOC'IDIDJC'JC'JC'J 

(NCIC'5CS(MC'I<MC^C'I<MCM<M 

1 1 1 1 1 1 1 1 1 1 1 1 

OiCPCPOOPCPOCOOCC 
H H r- 71 M 71 C 1 <M Cl 
CNCNC 1 (MCI(NCSIM(M 

1 1 1 1 1 1 1 1 1 

OPC5CPOPC5CPOCCOCO 
OCOdDCGCl-C: 
(M CN CM C^l Ol CM CM (M 

1 1 1 1 1 1 1 1 1 

©©©Tti^-rjiCDCDCD 
CC CO CO CM CM CM 
CMCMCMCMCMCMCMCMCM 

1 1 1 1 1 1 1 1 1 

0©©*D*0*OCMCMCM 

OOOhhhOO© 

CMCMCMCMCM01C-4CMCM 

1 1 1 1 I 1 1 1 1 

NCCOOHCOIOOM 

t-H r-4 i-H rH rH 

<N<N<MOCr^t^r>l'-!> 
<M CS 

i-iHrHOD 00 cD*C*O*C»OiO 
<N <N (M CO <N CM 

iocoeooor>i^oot^t>» 

©CPOPCPGPGPOPOOt'- 

rrCMCM©iO*OrHCMCM 

00 00 00 ^ CO CO *D CD 00 

1 -H 1 -H 1 -H 1 -H r-H rH 

+1 + 1 ++ 1 

+++++++++ 

++++++++++++ 

+++++++++ 

+++++++++ 

++++++111 

++++++111 

*0 *0 CO CO *—* N ”3* CD CD 
XXX03C03000 
rHrt hh(Nh(NC^CI 

1 1 1 1 1 1 1 1 1 

TpcDOOOCOCOCOOOi 

CDCD‘0CDCD'CDCD*0’TT 

777777777 

rHiHaiONOOCINMCCCCCO 
OOC. ChMtpiCCODCC 

77 1 777777777 

TpOdOTfX^MC 

iDiCTP'rr'Tj'Tj'iOCDCD 

1 1 1 1 1 1 1 1 1 

CC *D *0 CP CM CM CP CD 00 
iHiHiHihC^MCMcCCG 

1 1 1 1 1 1 1 1 1 

i-HrH©CM©CCt^ 0 C»O 
TJ1 10 © *0 CO 1—1 1 -H CM 

111111 +++ 

CDh-*CD©00CM*O©^- 
1 -h CM CM CM CM CM 

++++++111 

2 ^ 2222 *^ r " r_l 
II 1 1 1 1 II 1 

hNtpO'PIOCOhM 

»—* HHHHrlHriH 

1 1 1 1 1 1 1 1 1 

1 1 1 1 1 1 1 1 1 1 1 1 

OPTfCCSHDJCCCi 

H H HHHH 

1 1 1 1 1 1 1 1 1 

©CPCMCMOCMOCt^T-H 

1 -H rH H H H 1 -H 

1 1 1 1 1 1 1 1 1 

CPCMCC5CP CMCP0CC1 

1 1 1 1 1 1 1 1 1 

CMCOTTCO*—<C0»O©CM 

1 -Hi-HrHrHt-Hl-Hl-Hr-Hi-H 

1 1 1 1 1 1 1 1 1 

. 5007537 
. 5007544 
. 5007546 
. 5006459 
.5006482 
.5006471 
. 5006281 
. 5006281 
. 5006299 

. 5006079 
. 5006089 
. 5006064 
. 5005895 
. 5005909 
. 5005892 
. 5005898 
. 5005889 
. 5005876 

.5007477 
. 5007481 
. 5007479 
. 5006408 
.5006417 
.5006429 
. 5006293 
. 5006294 
. 5006300 
. 5006288 
. 5006292 
. 5006294 

.5007553 

.5007565 

.5007548 

.5006464 

.5006484 

.5006495 

.5006308 

.5006321 

.5006323 

.5007402 

.5007424 

.5007412 

.5006360 

.5006351 

.5006351 

.5006178 

.5006179 

.5006191 

.5006721 

.5006739 

.5006753 

.5005656 

. 5005637 

.5005613 

.5005404 

.5005402 

.5005405 

.5007581 

.5007580 

.5007570 

.5006500 

.5006509 

.5006515 

.5006345 

.5006348 

.5006365 


r- n n o o c co c <_ 

080S88S88 

lO LO 1 C o lO 10 1 C 1 ‘ 


CO N CO 1.0 o o >o 00 00 
NNCOCOtONr-COO 
HH0005 05 03 0 00 
CO 50 O »C *C lO C t-O *0 

S cccccccc 
oocoocooo 
10 to *0 >o *o *o iO lO >0 


__ __ ... __ . 05 C O'. N10 

io i-o Oi co 0010 -r ^ 10 c ifiiorHcocc 
lOioiC'T'TTPcococococoeo ccccor - 
NNNtOCCCCOCCCO 

888888888888 888:_ 

*0»0*0>0*0»0*0*0*0*0»0»0 *0*0*0*0*0*0*0*0*0 


COOOCCCOC05COO)iO 
C 03 h* co >" c: co M 

*O r T , TrTrTrCOClCMCM 
t- © © CO'^COO 
- 5COOOOOO 

_ _>cocoooo 

10 10 10 IO 10 10 10 ‘O »o 


CO O 05 C T»< OC CO ^ 
MCOfN^COOCOCOCO 
oCGCOCr^l'-cCTr-rr-^ 
CO C CO 10 LO 1C >0 LO «o 

888888888 

1010*0101010*010 0 


OOWOCKOC3CON 
'TOCOCOOCCfMOJOI 
CD CD CD »C 'O *C - rr TT 
N N -i CO cci CO CO O 

888888888 

ooooooooo 



iHHTPMOiHCOTPOO 
•O l"* CD *0 t>- CD ' r T CD 

1 H-H 1 H 1 OCONNCOO 

tjitptto*o*o*o*o*o 

CMCMCMCMHjiTrt-OO©©©© 
Tp Tp Tp CO CO co *o *0 *0 *o *c »o 

cc©©*o©©*o©t^- 
tT*0 0*0*0*D*0*0*0 

cc^'^'-rr'-r^^ocD 
10 10 * 0 * 0 * 0 * 0 * 0 * 0*0 

©rHCMtH-00 00TT*O*O 
* 0 ©CD* 0 * 0 * 0 ©©CD 

*0*0*0©©©00©CM 

TTTjiTrTr*o*o©t^r- 

D1 LO *0 00 © © 00 CM CM 
TP Tp CO 00 N 00 D D 

CM *0 00 CM 00 00 00 © *0 
© © GO 00 00 00 OO *D 

©©* 0 © 00 * 000 * 0 © 0 ©© 

TPTTCG*ONOCOt^©ODD 

©©©*D*C*C ©©00 

CCC)0©OrHCO*0*0 

CM lO *0 *0 CM (M © LO © 

cccccc^r*o*ot^-oo© 

OOOOCM*Ot'-CMCMOC© 
© CM tji CM 0C CO CC *0 Tpi 

CM©00DlCM*OCMG0»O 

©*OCC*OOC©rHTti© 

©©©©©©©©© 

000606060000000600 

t^^I^t^r^OCOOGCOOOOOOOO 

c 66 cc*oc 6 <oc 6 c 6 co 

*-H r-H r-H r-H rH i-H rH rH rH 

*0 10 * 0 * 0 * 0 * 0 * 0 * 0*0 
1 -H 1 -H 1 -H 1 -H i-H 1 -H 1 -H f-H r-H 

*6 ® cc «d *6 *6 tp Tp Tji 

rHrHiHrHrHr-Hi-HrHi-H 

Tp Tp Tp Tp TP Tp llj U5 JO 
HHHHHHHHH 

OCOCCOCOCMihtpO 

i-H © Tf* 00 © tji CM © CM 

©iDtj<iD©»OGC©COhh©© 

NtpCNOhNWN 

t>.t^i-H©oc©o 0 Tr*© 

t^©l>-©OCi-H©Tji© 

1 -H rH *0 CM t''- Tp" CM lO 1 -H 

CMi-hCMCMi-hCMCMfhCM 

CMCMCMrHCMCMCMHHCM 

i-hCMCMCMCMCMHi-hCMi-hhi-h 

i-H CM CM H CM CM i-H H r-H 

rH rH CM i-H i-H CM i-H rH CM 

i-H r-H r-H i-H rH CM rH r-H rH 

CMCMCMCMr-HCMCMrHCM 

© CM 00 © TJ 1 00 TJ 1 rjl 

TJ 1 ©©COTj*©t>- 00 'Tr 

H©COCMtP*CtPCOCOCG*ON 

© © © © nr 00 CM CC © 

CM00*O©00*O*OCDCM 

0CCDCMtJ«C©CM00*O 

1 '-CMI > -© 00 tU , 'TJiiO 00 

iO*D*D*D©* 0 »OTr *0 

io 16 *6 *6 <6 *6 *6 *6 *6 

dcD*DCDCD* 0 * 0 * 0 * 0 CM* 0*0 

i 0 iD* 0 Tr* 0 *D* 0 *D *0 

*6 ^ *6 *6 *6 *o ^ ^ *o 

Trio*o*o*d*b*OTr*o 

*od*o*o*o*od*o *6 


NHHNCOCOOOOOS 
CO CO CO 00 00 00 C5 Q 03 
CCCCCCCCCCCCOCCCCC 


TP rr Tf TT 'ST TP'T 


CONNCON^f CONOCOOM 
OOCONCOiHCONNCOOOON 

'r'rTpOOONNNCONN 

C0C0C0CJC3X03 03 05 C3OC3 

ecccecccccccccccoceccccc 


10 Ci N O) O CO CO c 


OCt^t^CO' r f" r t*‘OLO'TP 
COCOC0 03C3C3000 
CCCOCOCOCOCOTP'rr-^ 


OI0NCCO03 00WC0 

'pTpt'TPOOCOCOO 

CMi-^dCMTriOCOCOCM’ 

NNNTpTPTpcOCCO 

CO CO CO TP TP TP Tp TP 


OOMiOOCOTpTfOOCO 

CMcCt > »©©CM*OCMC$ 


© © 1 -h co co *0 *o *o *o 
cmcmccoogooo©©© 
ccccccececcccccccc 


M^TfrOOOIX'O 

CO*0»hNI'*COOtpCO 


OOhM(N(NININ(N 

Tp TP TP TT TP TP TT ^P TP 


•MTHNC0*0'OTpTPL0C0C0*r 

CO CO CO X X DO C5 C5 c. 03 05 0 

ccccccccecoccoeccccceccc 


CMCMCMOOOCOO©©© 

ecrccccccccccccccc 


(NOOOODON'PCOO 

t^C5t>-OCCi(Mt^.COi-l 

COCO T fOOC 5 *—'C-'fN 
COCOCOCCCCC 5 COO 
cocccocccocOTrrrTr 


8 


CXtPCOtpOO^* 

<NiOCOt^COCN(NC 

cocccdiococ’*ocdoo 

cocoocoeov*oio*o 

ooccco^r^^r^r^T' r r 


©00©©Tf00T-iCMCM 

COi-1 f -1 TP d 10 CO’’J* X 

NNoocc-Hciad 
!N N IN CC 00 00 CC « 00 
ccecccecccccoccccc 


© 

*^ © © 


ci 1 


•• . .8 
rH CM CM CM C 


G© CO © © dp © 

OINMNNCO 


! be 
. p 

t . : - 

© H rH I • 

cc cc cc r* ^ 


8 


••T WT '•T | 

© ci r^-’ ri oo oc oc © ' J.. 

CMCMCMCMCMCMCMCMCM »-< *-• 


cmcmcmcmcmdSc3c3cm 

>»>*>>&>» >>>?,£» ^ toibibbbflbcbctctiW) 

'P'P'P'Z.'P'P'P'PTJ ThThTh'ThThThTJ'ThT^ 'P r-^ r3 5 75 77 cc ^ 




CO 

cm cm CO CO 00 


H • • I • • | • • id • 

!©©©^HrHrH<N .*? . 
D 1 HH 1 -IHHHH TP Tp to 


CD * *t>. 

»o *o *o © © ci> r- 


+j+j+J 4 J+J+J+i+i+J 


wjmmwjmmmmw a&aa&&6.c.& p, 0 , 6 , 0 . 0 . 0 . 0 . 0 . 0 . ““Sf Sfg* tfSfSf S’ 

SS-.-.-.-.n-.a a,®®®®®®®© ®©©©©©©©o -J-j-®-; — -;-; — 

<;<;<; •< <;•< <; <t <J os kk k 00 mcg 00 k 02 0002 ocas cow km 


3 3 3 3 33 33 3 3 33 

*—5H-5*—>h-5h-5h-5>—5p-5>-5 


333333 P 


3333333%^ 

Ka^t-rsH-jt-sl-sh-sh-sPTS^-s^*^ 


ofififiQflaoo flOQooflflOfi flQQOQfififloflpfi fifippppoop qqqcpqqoqo rpppppprp oQooapiccsQ 


TT-f-^* 0 * 0 * 0 ©©© 

fq«pqpQpqpqp 5 Wpq 

* 0 * 0 * 0 ©©©©©© 

pqpqppfqMpqpqpqpq 

rPTfipiOiOO©©©©©© 

wpqmpqpqpqwwpqwfqpq 

TpTPTf* 0 * 0 * 0 ©©© 

WPPKMMWFOCQK 

TPiPTplO* 0 * 0 ©©© 

pqfppqp? WffifQfppq 

Tt<TjiTt 1 »D* 0 * 0 ©©© 

TPTp^*o* 0 » 0 ©©© 

pQPCCQPGCqCCQPQM 

rHCMCCT» 1 *O©t^ 00 © 

i-hCMCOtT©©I'^ 00 © 

HdcoTp*o©r-x©CH(N 

HHH 

i-HCMCC’T» , ©©t^CO© 

rH CM CC ^ CC © 

HHCMCCTj , iO©t > * 00 © 

i-HCMCC^J'©©t > * 00 © 


-4-S £ 

«h O 

CjfL, 

<D . 

£q 

Cfl rj-3 

i -1 O 

N pj 

Jh|j 

6 ^ "d 

£ 


<D O 

g&H 

“P 
» a 

. O 

o >-> 
£ 


•| I 

l£ 

°A 

. o 

O >-3 


** 

2o 

03 >-» 

n ^ 

CM TO ® 
«- 
b. ® 
o?Pi 

?C 


- B 

. 8 * 

o 

sii 

-T 5 

O^P. 

£ 


§2 

H 

o 


05 g ^ 
H a o 
oSftc 


« B 

_.B 

■o o 

BH 

2 f 

Os . 

'Js 

sc 
























































































Pendulum observations and reductions —Continued. 


164 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 




g 

cd 


£ 

3 


Ci n 


OrH 
IQ Q 
© © 

do 

OO II 

Oi n 


O - 

SI 


b* rH 

38 


82 

O *i 


o © 

CC II 

a> II 


oo 

CC- _u 
C 5 t 1 


O5CC0CCCCO0C0GCC00 0C 

>.d dddddddd 

rs cc cc oc oC' cc go oo oo oo 


OiOCitrrOcCirN 
C 1 C lO lO IC C ‘O lO >o 
lOiOiOiCiOiOidOO 


© 0 —«©ggodo 
*J> o 't c o 1-0 lO no 


W tO i-O OO NNiCC 
cocc^c^rc^roco-^ 

rr'^T^TT'-^rrj’r^rf^r 


ooooooooo 

OC cc X CC CC X X X X 

ooooooooo 


ooooooooo 


ooooooooo 

X X X X X X X X X 

ooooooooo 


X x 
X CO cc 
• u- 

*388 


© 00 OC CM OC 
COIC’VCCIC 
M CM CM O O O 


I 0 icici 0 » 0 * 0 i 0 i 0 i 0 

d 


’<J* 0 C 0 C'l^©CM©Tr© 
^•ifl^NNCCXCCN 
'©©OOCQOOG 
1 ^- b>- © © © © >*C no 

888888088 

iO iO iO »o no no no no o 


rj'-^OO’^XOOX 
o o o x x x o o o 

CDCOCOOiOiO'CiOiO 

ooooooooo 

ooooooooo 

iC i-O o »o O iC lO iC o 


O-^O^IMXO^O 
O X I- CM —' O- — — O 
WNNNNHCCC 

1 - t- o o © © o o 
ooooooooo 
ooooooooo 
o IC 10 O IC 10 C IO O 


O0t-hCM©CMCM©O 5© 
COCDiiSONCOSCN 
Tf'-^TT'XCCCO—• — —I 
b- b- © © CD O CO CD 

888888888 

LC IC IC IC »C IC »C IC ic 


e c. 


o {- X 

c- 

43-fc 


^ CO Ci 
X CC CC 
cc x cc 
.p.|^N 

•888 

© © © 


CM CC CC 50 Cl © 
c >c »C C IC D 

c^gcco 
lO iC iC § IC iC 


iriCiCUUUNXCC 
-——OOOXXX 
. © © ~ * - “ 


UNNCOOiCiCiC 

888588028 

lOiCiCiCiCiCiCiCiC 


»-HO(M'^-r i xc > cco 

oooxxxccoo 

OOOiCiC- «C*CiC»C 


HOtDN’J’CNHH 
OX X. — —« o O —' C4 
<M<MCSCMC1<MOOG 
UUNCCDC’i © 
OOOOOOOOO 
OOOO OOOOO 
lOiCiCiCiCiCiCiCiC 


ooooooooo 

ooooooooo 

u: UC IC IC IC IC 'C IC IC 


c o, 

szz 


-N 
O fe® 
£- 2 - 
5 


CC ®0 

■’■r CC —< 

•KRS 


|C»CIC 

d 


U* O CM —' CD O 
CO CC T !"• CD nc 
gggocc 

LC W Ic c IO IC 


NOOVCNMCW 

© x cr 1 - © © oc © 
—I — — OOOXXX 
N t'* N C © © iC iC IC 


LC ic IC IC IC IC IC IC' IC IC >C LC ic © © 


_ _© r- 

. . _ T ”0- CM -?< -T CM 
© © © X X X O CD © 
©©©1C1C1C1C1C1C 
OOOOOOOOO 

000000000 

■ “ ~ * — 1C1C1 


CC N (N N C) H c C C- 
I- l- © © © © © no 


: lO 


iC O iC lC >C iC O iC iC 


—• no CM O X O -r- CM I - 
I - CD X X l-OO^C 

■'T -"T x x x d: •-- 

t- t- r- CD CD CD CC CD CD 

ododddodo 

LO 10 10 no 10 LO © © LO 


<t 

03 


.G 

C 



Flex- 

ure 

»0 © © © © © »0 © lO 

—<rt—< 1 — 1 — 1 —« 

1 1 1 1 1 1 1 1 1 

1 1 1 II 1 1 1 1 

xxxxxxxxx 

1 1 1 1 1 1 1 1 1 

— 1 — 1 *—1 — 1 — " — ’ —( — 1 *-H 

t—( —' rH —1 r-H i-H 

1 1 1 1 1 1 1 1 1 

hhhh^hhhh 

1 1 1 1 1 1 1 1 1 

© 

Chro- 

nom¬ 

eter 

No. 

1841 

C5C3CXX0COOO 
b— t— I ^ © © © X X' X 

777777777 

<MCMCM©©©XCOX 
b- I- © © ©CD © © 

777777777 

777777777 

©©©XXX'»f^'D 

»c © © -rr 'T © © no 

777777777 

or CC CC N U N Dl Dl Dl 
© lO © © © © 

777777777 


Chro- 

nom¬ 

eter 

No. 

1883 

OQOQXeoepccooo 

D1 CM CM Dl 01 r; -t —• -IT 
<MD1D1D1CM<M<MCMD1 

1 1 1 1 1 1 1 1 1 

GOO^r , *rT? , ©©»o 
"C 1* Cl D1 D) ci N CM 

CM CM D1 CM D1 D1 D1 D1 Dl 

1 1 1 1 1 1 II 1 

CMCMCM — —• — XXX 
CMCMCMDICMCM — — — 
D4CMCMCMCMCMCMCMCM 

1 1 1 1 1 1 1 1 1 

©©©~r — -f*DJCMCM 
IO ©10 X X CO X X X 
D1CMCMCMCMCMCMD1C1 

1 1 1 1 1 1 1 1 1 

KrOWCCOJi”-’*' 

rf’t cc rt cc cc cc cc 

CM CM CM CM Dl CM Dl Cl Cl 

1 1 1 1 1 1 1 1 1 


> 

<£> 


<NNONWvT.<CN 


4©X^DIX©0 OOXI^iD-fCXX WMMNOCKWM 0 05300KWN- 


Pu cc 


I I I I I I + + + + + 


i CM * 

I I I + + + 


- + + - 


-+++ ++++++++ 


c 

o 


S 2 £ 

EH p,+» 


o 

O 


b-lOCC©b*©©T)>C 
© CD CD CD © CD © © 
CM CM CM CM CM CM CM CM CM 

I I I I I 


III III 


TP © © 
X o o 

777 


X © © 

© — C^ 
*—< CM CM 


—* X —' CM CO CM r- CM 

*0 © © t-* r- 000 

D 1 CM<MCMCM<MCM<MD 1 


t'- — OCOX—«<MOM 
-D © 01-00 — CC -i« 

1 1 1 1 1 7777 


1 1 1 1 i 1 1 1 1 


WCMNC 


—< oc b- oc o —< — OO 


-ITXO—'Xt^XO 0X0’—IN31QOCO OOOOO- 


I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I I I I I I | I 


1 CU< 

I I I 


T3 

© 

"o 

© 

y 

0 

0 

Chronom 
eter No. 

1841 

3 

8 

© 

Chronom¬ 
eter No. 
1833 


OffliflHtDNOHb 
XO—<XD1D1X<M<M 
NNCCNNUl-iCLJ 


■ r- t". ©_ 

"888888 

10 10 lO LC 10 10 LC 10 10 


»0 *0 *0 CM D1 CM 

f- b- © © © © © © 

888888888 

lOiClOiOiOUJiOiOLC 


t- l- D- © ■--- 

ddoooddoo 

© © lO LO iO lO lO no LO 


o o o o o o o © o 
o ooo©o©oo 

LO LO LO' LO © LO 10 no I.C 


U- 1-1 © O b- 
x r- l- © 
1-r^» b- © © 
1 - b- r- © © 
OOOOO 
OOOOO' 
© LO © © © 


8 S3 8 
© — © 
© © © 

888 

© no © 


NXtJ<hCCh©Xp 
- r-r^roxt^oxt 
X X X r- © no n 

•t^b^b^©©©CO©C 
or Q — — — 


88888888 
iO ©© ©©©©©© 


NH©ccO©’fDj: 
r-©i- — ro — oiroc* 
LO©©LQIO©COCOCO 

8888=8888 

©©©©©©no©© 


xx^x^xxx-^* 
o cyii , ow©<C’j' 
cc « co co co —< —« —• 
1-b* © © © © © © 
ooooooooo 

OOO OOOO O'o 
© © © © © © iO © © 


© © © i-O iO »0 CO X CO 
1- l - b- © © © © © © 

888888888 

iO©©nO©©©©© 


b- CM © © CM C- 

X X X I" l - no no © 

t'-D-D-©©©©©© 

888888888 

© © © »0 © © © © no 


Pres¬ 

sure 

J LO © © © b» © iO © N 
gcD©©b-b-t-©©© 

e 

^HX-'ft'-DJXOX'-* 
© © © © r>* x © lo »o 

■*s«©©r'-05©'*‘©© 
© LO © © L.O © © © LO 

0©0*-*X^G©0 
»0 © © © © © © »0 ‘O 

rt*nO©0’-H»-'DlX-r 
©©LO ©©©©©© 


i£s 

. 0 X X LO X © LO 0 0 
Cj;C5©CMCOCOCOCOCOCM 

OXOXXXCM©X 
*-^XXX©©>b-—'X 

XCMOXXCMb-XX 

ODCM’fiCOOO 

<M no CM i -O CM CM O X 

rHlJI'^NDl'tDrHCO 

XCMOXnOCMCMCM© 

OOOCXDOO'J”r 


© © S3 

h 0 .-“ 

- © *—< ^ H •—1 *-H 

0 CM CM Cl CM Dl CM CM Dl Dl 

05 ©i ©5 ©> ©5 ©5 ©5 O O 

HFlHHHHHNCi 

© CH-lr-r-IHNH 

<M<MDICMCMD1CMCM<M 

©©©©b^b^t^XX 

HHHHHrlHHH 

XXXb^b^b^b^OCX 

r-H r—< rH rH 4 rH »-H rH »—< 



gOibHNNOOXW 

'DlCMr-lCM 

b^t^-x©©0©5©©5 

t— WNOOCCDI^Ch 

0XD-0©XXXCM 

t^D^NOOOOlOO 

»-• 

S 

hhhhhD1h>-ih 

r8 Dl r8 iH i-4 Dl H i-i Dl 

HHHHHHHrtDl 

i-IhDIhhhhhh 

•H 1 
© 

Ini¬ 

tial 

^OODWUCCO©X 

l'-l'^r-4©©rr'Tj«rcO 

("DiCCO iCt^^HCC 

05©0^©X©©I>- 

OOMOOH^NOh- 


Sd©©©©©©©© 

© TT ~3* © © © © © no 

©©^j4©©©Tj5nod 

-r-bnonodTrddd 

LO © ©' d © © d d d 

•S 

Chro¬ 
nome¬ 
ter No. 

1841 

XO*-4XCM©©CMM’ 

TfDl-^CiCMF-iXCi© 

XO-T©DlXXO© 

t>-©D-©XX©X^ 

•^OCMOCM—<X©© 
CM-^©5©5©t>-X©© 

^hCOXD1©C^ 

<CMnO©*sJ<D- 

©C5©XOOOXrH 
©—<CMCM©b-r-iCX 

© 

O —. 

G 03 
© > 

z — — ©•-iDicMcocod 

DlDlDlt'-NNCCCCCC 

XXXXXXXXX 

XCMCMX©©0 C5CC 
COXXXXX005C5 

xxxxxxxxx 

<MDi^odd-4^d 

XXXXXX^”^^ 

nmMccNNXNL'j 

b^XXXXXOiOO 

XXXXXXXXX 

rH CM X © © no © © d 
(N Dl Dl b- I- '/ CC CC 

XXXXXXXXX 

*0-2 

6 

5 SZw 

° u, * 

O c ^ ^ 

©^*©T«©DlXXr’ 

00»-<©b-b-©05© 

^■^©XXCMXOX 

Dlr-CMOM^WOCO 

^CMCMXC5CMf-igCX 

x©0’<r©cMXX'^ 

nOC2'^©Tr©CM’-«'^ 

CO c5__iCM' , T'''* , Cir— 

0 

0 

«cd©idxxdddo 

r-HHOO©NNX 

xxxxxxxxx 

doo^rx-^LOLOio 

XDIXXOCXOCOOS 

xxxxxxxxx 

CCCO©^ X © © LO b'- 
XXX05005000 

xxxxxx-^^^r 

XXdCMCMCMXCMCM 
CMCMXXX XC50505 
XXXXXXXXX 

NoododcSdoH 
H h CM 1^ N N X N CO 

xxxxxxxxx 


Date 

1915 

Aug. 11. 

Aug. 11-12.. 

Aug. 12. 

Aug. 12. 

Aug. 12-13.. 

Aug. 13. 

Aug. 13. 

Aug. 13-14.. 
Aug. 14. 

Aug. 19. 

Aug. 19-20.. 

Aug. 20. 

Aug. 20. 

Aug. 20-21.. 

Aug. 21 . 

Aug. 21. 

Aug. 21-22.. 
Aug. 22. 

Sept. 15. 

Sept. 15-16.. 

Sept. 16. 

Sept. 16. 

Sept. 16-17.. 

Sept. 17. 

Sept. 17. 

Sept. 17-18.. 
Sept. 18. 

Sept. 22. 

Sept. 22-23.. 

Sept. 23. 

Sept. 23. 

Sept. 23-24.. 

Sept. 24. 

Sept. 24. 

Sept. 24-25.. 
Sept. 25 . 

Sept. 29. 

Sept. 29-30.. 

Sept. 30. 

Sept. 30. 

Sept.30-Oct.l 

Oct. 1 . 

Oct. 1. 

Oct. 1-2. 

Oet. 2 . 

Posi¬ 

tion 

ooooooooo 

ooooooooo 

OOOOOOOOO 

ooooooooo 

QOOOOQOQQ 

Pen¬ 

du¬ 

lum 

■^■'fTr’LO©©©©© 

'^•’sT'n*©©©©©© 

■^•^^©LO©©©© 

TflT^^lO©©©©© 

pqpq»ffl«pq«p;p; 

^^4TfLO©©©©© 



HDlCJ^'iOOb’XD HDlCCViO©b’XD H C4CC ^ iO<D b>X D »—1 CM X ^ © © D- X Cl HCMCC^»ODNXD 


D 

O 


*o 

a 

c5 


a 

c 


cs 

m 


*P 

G 

o 

G 0 

.-43 


tsP- 

'O 




D2 O 

go 

o’ -1 


ns & 
u, o 

G . 


§0 


« ts 

S ° 


go 
O c 

J3 

o 


SO 

o a 

X3 

O 


O 
z 0 

m2 

o 

.►-» 


Z 


3 QJ 

a > 

1S4 

nn., 

well 

cz> _r 

•“« G 

o . 

o • 

!>• •> 
Sg 

5 f H 

3 ° 
o^Ph 

o 

c as 

6 *^' 


z 


z 


z 


z 



















































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


165 


cm *-< 
CO o 
tO o 

o o 

00 II 
C3> n 


Cl 71 


82 

* 71 


82 

Cl +1 


82 

Cl 71 


Ol *-* 

28 

00 r-H 

38 

8® 

Cl 71 

82 
d 71 


N Tf LO N X (N X -H OJ 

cococococmcocmcoco 

It! >0 lO C LO 1.0 to *o 

ooddoodcd 

OOXCC X /. X X X X' 
ddddddddd 


‘223^o*-«(m^coo«ocoo><n 

lO o IQ »C lO LO lO lO lO lO >o >o 

OQOOOOOOOOQO 

XXXCOOOOOOOOOOOOOOOOO 

dddddddddddd 


SxSSSSSSa 

03 0105 03 01010 0 0} 


CMiOOOt''r-tcOcO»-lCO 

cocococo-^^ro’^ 1 '^ 

cococococococococo 

sssssssss 

ddddddddd 


o oo co to oo CO to t*- CO cooN»ooiHcoooto 
9£2Q2£2 £££t;!22£ , '*cO’«*cocO'+coco'*j« hhmhhnhhh 

OOOOOOOOO HHHrlHHHHH HHHHHHHHH 

8 x8gB ^ y ' S § ^ § x' 

Cl Cl Ol Cl Cl Cl Cl Cl Ol Cl Cl Cl Cl Gft Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl Cl 


O — © CO h* CO »0 V . . 
NMWhhh Cl Cl Cl 
N N l>. CO CD to lO O Ul 
ooooooooo 
000003030 
to iO lO »o >o »o »o <o o 


. _: Cl Cl O 

N l« N O CO O CO CD C lO O >0 

£S222 ooco Q^5 

003000000000 
I0i0i0»0i0i0 0i0i0i0i0i0 


ocox^iocm©-^© go ^ oo oo co ^ oo ^ 
to O Tf 00 N c O X N -hOIOtJCMOIO^W 

^ ^ M :Q !N O) Ol -H o O NNNHrHHOlCJlOl 

X X oo t>- r- i" r- t— oooownnncocc 

83888888 88- 



O »0 ‘O tO *0 *0 to tO 


NOOMClCOHlNCOn 
NNCClCiOGOQClO 
NNNhhhOCIO 
ooocg^t^t^-t^r^o r- 

• 0 >oto»otooto»o»o £o *o»ototi5tot?5to *o §toto§»o§§8§ 


COOOQHMOOINHCO 
OONW-ct'CO'ff ^ 
HINWHHHCICIOI 
N N N CO CO to O LG »0 
© © © o o o o o o 
ooooooooo 

lO iO iC O iO iO >Q O iO 


NOOOOOOHOHHMN- . 

<-chh>hhhhhhO)G03 

N r* h- C CO CC CO CO CO LO >o o 

ooooooooooc- 

OOOOOOOOO oc_ 

lOOLOOiOiCllOiOOiOiOO 


NOOCICOIOMNCOIN 
rtINMMONiOOOO 
COCOCOIO idOCOCO^J 

- -5 »c u5 


fNiOcOl'-'^ONOlCl 

M'-NcOcOOtJO" " 
N N h* (O CO CO CD C 

88388§3L _ 

*o io »o *o to tO tO tO tO 


00 CO CO d W O N H N cDOOClMOTfCO^'f 
IO *0 N t'Qiqo 00 HHO^COCCiO^^* 

COCOCOCNOKMOOO C) M ^ 05 Cl a 

X X X I- 1 ^- I- 'X 00 CO t"» !■» !■» O CO cO 

8888883 888888888 

tO *0 »0 »0 IQ lO lO *0 to to to »O to LO to to to to 


x^ lOtOlOrHrH^lO 

coe-t>-d 00 d©d© 

(NNINHHHCaO 

OOXMNNt-NcON 

888883838 

to ‘O to to to to LO lO to 


OMN'frHCONOIN 

p-(^C3CO'^(N‘0'tco 

C^C^HHHHCldd 

M'-NOCOCOtCOO 

0000003 o o 
ooooooooo 
iO ‘O to »o o »o »o »o to 


OCOCOXMOOl^f’tOl^CO 
dONHHClOHX^ICSO 
— < —< ,-h — O -h — iOddd 

NMnCOcCCDCOcOiO o to 

888883888888 

to to to lO to to to to O to to to 


COdOC. OhXXW 
MC^XNOcOiOCON 
OOOtOtOtOCOCOCO 
CO o o to »o »o to «o tO 

888888388 

tO tO tO to O to to *o o 


^lOOOTfCCtDOOH 

COCM©CO*-H©tOCM*-H 
NNOCOCOcOrfTf'fli 
N !>• I - cO CO CO CO CO CO 

883S88SS8 

to O IO to to to to to to 


§8383? 

5 to to to to ti 


HTfiOXOMO^tO 

M 04 Cl T}< Tf rH to to (N 

oo oo go r— 0 — t'- o ■- 


IOMOWHHMNO 
N/jtOOONOOlO 
iNOlMMHHjdC 
XXXr-NNl^cDl- 
-lOOOOQO 

S O ©© ©o 
lO to to to *o 


^'ll'll ’ll CMCMCMCMCMCMCMCMCM OOOOOOOOO HHHHHHHHH CcCCcOcOcOcDCOC 

H HHHHHHHHH HHHHHHHHH HHHHHHHHH 


I I I I I I I I I I I I I I 1 I I I I I I 


1 I I I I I I I I 
§8333333 


I I I I I I I I I I I I I II I I I I l I 


o o o o o o < 

H pH pH pH pH pH r 

I I I I I I I I I I I I I I I I I I I I I I I I I I I 

i” f'* t— *—• ph •—* t— i' f- OOOMmwhhh i- t— co co co 
CDCDCDXXXCOCDCD d d d d d O O d O GO 00 GO Ol d d 

I I I I I I I II I I I I I I I I I II II II 7 


pH pH pH r-H pH r-H O O O 

CM CM CM CM CM CM CM C l Ol 

I I I I I I I II 


o to to t 
CO CO CO c 
CM M CM C 


! tQ 40 to tO to 
) CO CO CO CO CO 
I CM CM CM CM CM 

II I I I 


to to to 

CM CM CM 
CM CM CM 

I I I 


<M CM CM tOtOOHHH 

I I I l I I II I 


lOCO O O O —4 T-i pH Q O © HHH^TjlTjlHHH 

1 to to 30000000* CMCMCM-HpHphCMCMCM 

r-H r—• ph ph ph i—i H ph —h CM CM Cl CM Cl M M CM C4 CMCMCMCMCMCMCMCMCM 

I I I I I I I I I I I I I I I I I I I I I I I I I I I 


HHOXNNXGD cm CM CO to c 


+++++++++ 


5 CO ph 
) 

+ + + 


I ++++++++ + 


+ + I I I I 


CO CM CM O CO CM 
+ + + + 


+ + + 


11 + 11 + 


O^CMOCOtOCMOCM 


+++ 11+ I 


cO CO 1*0 CO Cl X X O Cl 

N N Cl Cl Cl H H r—i 

+++++++ 1 

CD pi* i-O p? Hi X O Cl N p^ tp 03 
CO X tp |p I' CO CO lO pf X 03 X 

pH pH pH pH Pi pH pH pH pH pH pH pH 

1 1 1 1 1 1 1 1 1 1 1 1 

d CO p£ CO P^ to pH CO CO 

tpxobxdddoo 
P}| Pl» pf P}< P»< pjc pjc ID to 

1 1 1 1 1 1 1 1 1 

HXXXrfcDtOXO 

ddOdCMpHCMcOC'l 

hhCIhCMCICINCM 

1 1 1 1 1 1 1 1 1 

COMOXX'OIpOh 
pf HxmcodxxH 
xf^cocoeoco'^’^to 

1 1 1 1 1 1 1 I 1 

rfXOXNXOOcO 

ccr-ioodddood 

pH pH pH pH 

+++++++++ 

*OX Cl NrHXX 05 uo 
pH CM pH CM CO tO 

1 + 1 1 1 1 1 1 1 

XXO^MHONH 

1 1 1 1 1 1 1 1 1 

Cl 03 X OHp d X C Ol i-O N X 

pH 

1 1 1 II 1 1 1 II 1 1 

rpcoxtpcidocDd 

pH pH pH 

1 1 1 1 1 1 1 1 1 

OOOCOrHt>COOOl^t'- 
pH pH pH 

1 1 1 I 1 1 1 1 1 

OOCMdCMCOGOdOOCO 

pH pH 

1 1 1 1 1 1 1 1 1 

Oldt-XNOXNOl 

pH 

1 1 1 1 1 1 1 1 1 

NhXOXOXNpJ 1 

pH pH pH pH 

1 1 1 1 1 1 1 1 1 


NflUOtCOCOOCCl 
Hd^tONf^XClH 
CO CO CO CM CM C4 C O — 
l- t- t- CO © O CO CO CO 


O tO O tO to to to to to 


: m co to r-H r ^ cm cm co d co 

1 M H X Tft to CO 'T -f to CO CO 

■ '-O O 'C t *f pf *t Cl M Cl 

- r - i - co co co co co o co co o 

lOOOOOOOOOOO 
1000 0-0000000 
It0t0t0*0t0t0t0t0»0t0t0 


CMCMCMHHP-iCldCl 


. ^ JNOH^X 
30005dSlXXN 
3 X GO CO © CO CO CO © 


cOONOtOci 
(p ’D (N pf 70 C 
X X X N S t 
x x x t- t - r 

88888 ? 
to to to to to t 


1 co CO CO cOOCMCOdO'OtOd 
)H1«N Ol X. rf t-O t-O l>- O t>- 

- CO CO CO «-HCMCMHHHCld d 

- I - I— !-• X X X N N N CO CO V 

§888 88888888‘ 
1*0*0 0 tO *o o *o *o *o *o t 


jmmcOWhhh 

‘xnnnnnn 

18f 


CO Cl t- CO PC CO to PC* 00 
OOdco^rcocOcoco 
pj* Pp CO CO ^ CC p- OT’O 
I— 1 >- co CO CO CO CO co 

ooooooooo 
to to to to to to to to to 


P" fp X X X O N X Cl 
©©©t-Hph-hX© - 

■ 1 M CO CM f-- 


CM C h X X CM*—<dCMcOt'»p^ 
-icjOpcPt'dprxHHiox 
CO CO CO to to to to to to CO CO CO 
fp N Ip O CO co CO CO CO O CD O 

o o o O O C- 

O O C O O C 


to to to *o *o *o LO to to to to to to to to to to to 


fp. tO o 

ssss 



00 CO M to to d p^ CO to 
pfiOMXOXiCKO 

~~8S8L _. 

tO tO tO to tO t 


_ 

- X X l-NM^NN 

“3888888 

LO *0 to to *0 to *o *0 to 


-HCOGOCMCMr-Htp-cOOl 
< pji X CD tp CO N 03 CD 
- O CM M CM O O O 
• r^. r- t 


Jpf‘COXPJ'CIOX 
c iXO'CCl ‘O fp O- 
'^i-pr^cicici 
1 S N N f p |p f- 

‘ 188888 
Jiooiotoio 




pH CM CM to CO O to CO t-p 
to to to to ‘O to to 0 to 

cOC-NOXMNr^COOHX 

cDc0cDNNXXd05C0CDCD 

-^p^pf HMXXP^ Pf 

t-- to *o co co co *o to «o 

XHXdXOXCMO 

CDNI'-tOcOXXXd 

XXMlOdXHX^ 

cO co cO co co cO co co cO 

t>.^XQCO^CM^rt| 

COXOOt>-X?ONOO 

NdHXCDC5HP}lCO 
tO to O CO CO CO CO CO CO 

xxoxxxoox 

coco^co^rtor^-ocM 

to O 00 to to O CM CM O CO O O 

CMOtOOOOCMCMCOQ 

rfcOOCOl-XI-OO 

to CM to CM to to X X to 
lOipoot^eorHcococM 

to to 00 to <X> CM CM to O 

CDOrHlONP}'Pj'P?<d 

OXOtOXtOCMXCM 

Xhp-»0!OONXN 

CMCMtOOOCMiOCMCl 

HdOpjnopjiiodw 

■^+ + + + ^^•0*0 

cdoicidciidcdododdd'd 

pH pH pH pH pH pH pH pH pH pH pH pH 

OcDcDCDCpdcDNI' 

CMCMCMCMCMCMCMCMCM 

oidddooooo 

pHpHpHphCMCMCMCMCI 

•o-^ + cdco + tdcot- 
CM CM CM Ol CM CM CM Cl Cl 

r-H CM Cl CM Cl CM CM ci CM 

pH pH pH pH H pH pH pH rH 

»d + to»otdidtdtdcD> 

pH pH pH r-H pH r—i r-H fH pH 

NtOOXOCOpfO 

dcDNiOMI'-COClOOMO 

^tOCMtOdOOOCMCO 

lOO^dNOiCOO 

DdXHdiOXXH 

COtOp^COCOCM-^CMO 

CDXXdXOiOXI- 

pH pH ci pH p! CM CM pH Cl 

pHpHpHpHpHpHpHphMpHpHM 

PH pH Cl pH pH c^l pH pH Cl 

pHCMHHpHpHHpHpH 

pH r-H pH CM pH pH pH pH pH 

pHpHpHpHpHCMpHpHCM 

HtHHpHHCilHOCi 

CNdXONdrtCM 

iCXCDfDXOCl'Dd’DO 

XONXX-fCliCCM 

t^CMO-^oddcoo 

Ot'»XX«NHHO 

NMCdXCOdXN 

cOcOCOphCMhOO’* 

■pt + + + * d *0 tri 

tdtd + td + + td + + cd + ^ 

^^10 + 0+10 + ^ 

tdcd + *d + + + + td 

lotd-^to + ^totocs 

to»o + + + Tf + -r + 

+ to + tdtdtdtd»dtd 

ICO^XO'OHCMPJ' 

HDXHdONO'O 

OpfiC 00 CO CO CO Cl HC3 CO *h 
d 00 CM 00 CO O 00 O CO CM CM to 

O^CO-ftOr-HpHOlCO 

CMCOtOOOCMCMOt^-^ 

N'DdONXtOXX 

TfOtCOXN'tNX 

XXCMOOCM^X-H 

PH CO to 3 Tt< tp 1*0 CM 

oNijHOOocoo 

tOCMGOOt^CMTjtoOr^ 

O^OXd-HtD'DQ 

XHdOpiOlXX© 

ci-Hodcioi^-Jd 

p^pfpf 0 0301 -hhO 
COCOCOTt<COCO'^'Pt < pT 

cdcicdcdcdodcdcdcdocdci 

X X X X X X X X X O 05 C5 
OOCOCOCOCOCOCOCOCOP^COCO 

NNcDXC3XrHC5X 

■C'J'^COOINhh 

COCOCO^-r^r^TfrrTft 

pHp-ioOXdl^f^OO 

pHpHphO*0»0c0C0C0 

COCOCOCOCOCOCOCOCO 

ddXXXdXNcD 

XXXddCMddd 

OICMCMCOCOCOCOCOCO 

td + coOdcidcdod 

OOOtOpfpfiOiOiO 

xxxxxxxxx 

CldXHNHOOX 

COC5T|<-}'pJUCiO^ 

CMCMCMCOCOCOCOCOCO 

CDXO'DNCIXOO 

Od^cnoHOHX 

-fptClXHOOMClNXCl 

cirHTfCixxt'X^'rt^ci 

dCMprt*COQOCMXCMOO 

t'-pHQOiOOOOlOcOCM 

-f pf X N O O d d O 
WOdMXHOHtO 

CMCpfXOO’t'pfd 

OPfXpHCDrHdcDX 

rHdXOOdTt<-fO 

c-ooxt^roxt^dpH 

lOCMCnoxcDHOt^ 

COr-HpHOCOCMd-^O 

cd od »d + »d to cd »d 

XXXC3000 00 
COCOCOCOCOCO-^rtt-r 

oocddC'icMcdc v icM + + cdtd 

C1WC1XXXXXX05C105 

COCOX3COCOCOCOCOCOCOCCCO 

CMCOCMCMCMC'lCCcO CO 

^-fTt<OOOpHpHpH 

COCOCO^’^^r^rJtTjt 

NNI^XCMMO-Hd 
O O O tO tO tO CO CO CO 
xxxxxxxxx 

t^oiodcid + cdco 
t- l- X -H h pH cm cm cm 

CMCMCMCOCOCOCOCOCO 

pHOQ-l<*rtt + rdCMHtt 
O 0 O -r pf V tc UO ID 

cococococococococo 

rfFHtdcdcdt^Tjt^eo 

03C3dMXXTl*P)lTjl 

CMCMCMCOCOCOCOCOCO 

8. 

8- 9. 

9. 

9 . 

9- 10.... 

10 . 

10. 

10- 11... 

11. 

•CO • 'h* • *00 • • d • 

• pH • • pH 1 • pH • • pH • 

to »o cd cd ci fp co co oc d 

r-H pH pH pH r-H pH pH pH r-H pH pH pH 

• M • • *f • • I s - • 

•CM • • CM * • CM • 

• 1 • • 1 • • 1 • 

CMCMCOCOCO^CQ'-Dt^ 
CMCMCMCMCMCMCMCMCM 

• pH ••••••• 

; ;cj» ; ;co ; 

CO CO CO 

.9. 

.9-10... 

.10. 

.10. 

. 10-11.. 

. 11. 

.11. 

. 11-12.. 
• 12 . 

. 23. 

. 23-24.. 

. 24. 

. 24. 

. 24-25.. 

. 25. 

.25. 

. 25-26.. 
.26. 

• pH • • pH • • r-H . 

COcitJt-It^ooQO^oi 

HHhhHpH h p(H 

4J J +j +j r- 

0000000 CO 

ooooooooo 

. 1 — 

000000000000 

ooooooooo 000 

OOOOOOOOO 

OOOOOOOOO 

^ r* ^ r‘ •* 

OOO OOOOOO 

OOOAAAAAA 

OOOOOOOOO 

aaaaaaaaa 

OOOOOOOOO 

AAAAAAAAA 

>>>>>>>>&> 

OOOOOOOOO 

QOOQfiflftfifl 

QQOGQ3Q03GQO 

000333330 

000333333 

CififtPOOOQO 

003300303 

OOOOOOOfiO 

pf! Pf Pf if J 'O 1-0 CD CD CD 

Pj< pf *f lO »0 to ‘O i.C lO CD CD CD 

pjt rt< t}< tO «0 »0 CO O CO 

■pf t*< tO 0 »o CO CO CO 

TfpJipJitDiOiOOXcO 

pcqpQpQ«pQ»»« 

pfpfpf»OiDX'D3CDO 

pqfqpqpqpQPQpqpQpq 

H^TjlH^lOtOtOCOCOCO 

pqpqpqwpqpqpq^fq 

*-HCMCOTf«tOCOt^-GiOd 

HCMX'tiOCDNXdOHCM 

pH pH pH 

rHCMco^tocorp-ood 

Hdx^ tocor^Xd 

rHCMco^iocor^ood 

HdXPftDONXd 

rHdXPtlOCONX O) 


2 0 

§ 

5*. 

9d 

C3 n * 

a l 

O 

- O 

87 

5o 

"1 • 

is 

oS a 

"0 

Ol-> 

A 

A 



ft 

IS 

a,& 

°o 


5S 


o>- 

'A 


OPh 



b&— 

ll 

•n^ 
So 
a 
1 


W 


os 

ofw 

A 


3 ^ 

^2 O 
720 

Sfi 

.a 
^ ° 


09 

d* 

5^ 
















































































































Pendulum observations and reductions— Continued. 


166 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


0 

OS 




o o 
00 41 
05 II 


05 i-t 

mn 

“8 

00 O 
05 O 

O o 

05 O 

00 ii 

05 ii 

S-H 


COOOI>-OOi- 4 TrOQt'- 
^ N N Ol N (N CO tM (N O) 
^OOOOOOOOO 

5*0 OOOOOOOO 
rvOc 00 OC 00 00 00 00 00 CO 
HO-.050505C50050505 


OCOIOOONOC'IOO 

acsoccaooioo 

OOthOOi-iO*-h»-i 

ooooooooo 

OOOOOOCOOOCOCOCOOO 

050505050505050505 


05 10 NOWCOOMO 
COGCOOr^C 0050 C 0005 
05 05 05 05 05 05 05 05 05 

05 05 05 05 05 05 05 05 05 
050505050505050505 


T 3 

o 


0 

C 3 


iC H H M Q CO 05 00 O 
hOCCPNHCONM 
lO iO to rr rr rr M M M 

• az 60 co l- r- i- 
<o OOOOOOOOO 

ooooooooo 

•O to If 5 »C O 1 C lO ic 


(MOlCDOO^WM^OO 
M(NOCD’t(NO' 1 , (N 
COCOCO<M<N<MOOO 
oc oc go r- r- r- t>- 

8 00000000 
OOOOOOOO 
10»OICICIOIOIOIOIO 


M'COOl’f CDOHHrf 
OHOiOCOOiO^IM 

ocooLOimocococo 

ooocccr^r'-r^r^i-'-f'- 

ooooooooo 

OOOOOOOOO 

io io >o »o m to »o io io 


<D CO o ?C T}i CO O Tfi 
KttOOOHHHH 
<M<M<M<M<M<MOOO 
CO OC CO N N I'U- U- 

§ 00000000 

OOOOOOOO 

ioloioioioicioloio 


Tfir)<NNMH 

O 00 -T rH CO <M 
rf CO CO o <c <o 
on cc co co cd co 
O O' o o o o 
O O © O O O 
loicinminin 


S d„ 

OGW 
° 5-00 
o ® 




m^OHNNOiiDCO 
HC 5 H(MHHCO<Mrr 
»C rT lO Tji rr -r <M CM <M 
• 00 00 00 r-~ t— t— l — L— I 
'OOOOOOO'OO 

ooooooooo 

ininioioioininicio 


^NHH’tcoomm 
^COHDTTCOUO^CO 
COCOCO<M<M<MOOO 
OO CO CO N l - N N (>• 
OOOOOOO'OO 
OOOOOOO'OO 

in in »n m in >n in »n >n 


g (N- 0 * 1 , 'n'(M’fC'i*t 
H r- m CO rp rr CO 

co co co m in m co co co 
oc cc oc r- i- t- i - 
ooooooooo 
ooooooooo 
io in in »n in in in »n in 


©rrcOMMoOCO<Orr 
rr C5 05COHOCHHH 
^MMMMMMOOO 

CO cc oo oo I s - i- t~ t- u- r- 
C»OOQOOOOO< 


1<5 00 05<0 0 !N 
|w 05 N n C4 H H 
‘ CO CO CO CD CD CD _ _ ^ 

ig'g'gSSSse-e. 

!Joooooo 
CO lO lO »D »C iD lO 


a o ^ 

0 A Oi 
o u GO 

9 - 2 * 

s ® 


inoomcocoosoiHcD 

-■OOSOLMOCOCOH 

i-C lO rr -r -r M <M M 
• OC' 00 CO L- 1 - l- I- 
5000000000 
OOOOOOOO'O 
ininininininminin 


©DMDrPHCD^H 
(M <M O ^ H CD rf O 

COCOCO<M<M<MOOO 
00 00 CO t ^ t -- 1^ r- 
OOOOOOOOO 

ooooooooo 
»<: <n in m in in in m in 


Nrp'tTPOjeocnoco 

O H o lO CO C O V H 

cDcDcommincococo 

cococct^t^i^t^t^r^ 

ooooooooo 

ooooooooo 

ininminin»nininin 


CONHODHCODI' 

rr '-C c o O 1 o <m >— 1 rD ^ 

/r <M <M CO <M CM <M O O O 
W CC r/) CO N 1 ^ N N L- N 

QT. OOOOOOOOO 
^OOOOOOOOO 
wicininininmininin 


(M H D CC' ’t >C CO CC O 
m»-< 05 C<JOTjiMGCCC 05 
®^«CODCOD<N(NN 
CO CO 00 CO CD CD CD CO CC <0 
QT'OOOOOOOOO 
”1000000000 
Hioininminmininm 


X CD 

£5 


OOOOCOGOOOOOCOGOOO 05 05 0505050050505 

I I I I I ! II I II I I I I I I I I I II I I I I I 




I I I I I I I I I 


ooooooooo 

HHHHHHHrHH 

I I I I I I I I I 


ca 

6 

2 

T 3 

a 

+ 5 > 

fl 

<D 


a 

o 


o 

O 


c3 


^ S <3 o 
gc 


* a ^ .» 

H © <D O W 

g^z;® 


i i i i i m i i i i i ii i i i i i i i i i i i i i 


2 cococo»-<i-^^rfiTti'<f 

COcOCOCOCOCOCO’^'^'^ 

COHHHHHHHHH 

H+++++++++ 


f* O'. 

T* <M 

C0 + 


M M © 05 O , 


+ + + + + 


ooooooooo 
cccococoeococococo 
<M<M<M<M<M<M<M<M<M 

I I I I II I I I I I I I I I I II I I I I I II I I 


*00003005000 

NMnNwmcoW'i' 


*& 

“ t- 

cc ^ 

1-< 4- 


OOCOCCCONM-' 
<M <M <M O O O 
rp rjun m m in in m 

++++++++ 


S 3 

Oh to 


Sag 

EH 


NOfMCOHHL^CON 


NHH ^prprPH Or-I 
r —1 T—4 H H H 

+++++++++ + I++I+++ 


T—<COCOO<M-—iCOiOr 


+ I ++I+++ 


icn^HooNHoo 


■++ 


(MNOCOCO NCON^ 
<M N M CO CO M M M M 
<MM<M<M<MM<M<M<M 


I I I I I I I I I + + + + + + + + + 


M tT i—I tt i—lOMO 

mcoMoomcooooooo 

M M M f ■ 


- + + 


HCO'OOOOTP^CO 

©0©0»-H'-<COM<N 

MMMCOCOCCCOCOCO 


(DOOONDOONM O O O O CO M O 00 r 


OOOrH ooooco 


I I I I I I I I I I I I I I I I I I I I I I I I I I I 


t^MOt>OOOOrH 


I I I I I I I I I 


OMO»—<*—<OOCOO 


I I I I I I I I I 


T3 

o 

-*-b 

CD 

O 

t- 

K 

o 

CD 


Chronom¬ 
eter No. 

1841 

.<!. 

0.5008852 
.5008836 
. 5008856 
.5007773 
.5007763 
.5007760 
.5007567 
.5007550 
.5007570 

.5008507 
.5008521 
. 5008507 
. 5007506 
.5007503 
. 5007475 
.5007303 
. 5007287 
. 5007260 

. 5008630 
. 5008676 
. 5008684 
. 5007631 
. 5007626 
.5007576 
.5007382 

. 5007384 

.5007360 

1838 

.5007920 

.5007943 

.5007953 

.5006905 

.5006931 

. 5006964 

.5006797 

.5006801 

. 5006802 

OCO^CDCOH 

kOONhhh 

' rr co co o o o _ _ „ 

i'COGOCOOCDcOC-, ■>? 
,44000000 r 3 .r 3 .ry 

.ioooooo 

“ iO lO lO lO lO ‘O 

d 

T3 

O 

’C 

o 

p* 


Chronom¬ 

eter No. 
1833 

s. 

0.5008981 
.5008979 
.5008967 
.5007908 
.5007902 
. 5007885 
.5007704 
. 5007693 
. 5007680 

. 5008594 
.5008587 
. 5008570 
. 5007584 
.5007566 
. 5007516 
.5007375 
. 5007351 
.5007311 

.5008711 
. 5008752 
. 5008748 
. 5007710 
. 5007710 
. 5007649 
. 5007482 
. 5007468 
. 5007425 

1838 
. 5008166 

. 5008199 

. 5008219 

.5007163 

. 5007208 

.5007247 

. 5007081 

. 5007085 

. 5007086 

1838 

. 5008247 

.5008231 

. 5008166 

. 5006404 

. 5006444 

. 5006425 

. 5006059 

. 5006059 

. 5006056 


Pres- 

sure 

JHMCOCOOM’PM 

fcinininDDDu'inm 

s 

HCOlOHC5inC5HM 

<O<OO<OCOCO 1 OCDO 

TPHOOOXOOOOCOH 

t^Cit'-CCOOt'^COOOOO 

ccoincoHcc'toow oosocncDNcoinm 

O 1 O<O 1 O<O<OIO 1 O<O iO*OOiOiOiOiOiOiO 


ii§ 


.OMOCOiOMiOMiO 

^cn^'incom’cpTpTj'co 


ooor^oot^coo 

oooco^-^rot^-J^ 


ooor^t^u-r'-t^o mmmcococommm 


OOOOOhhMMM 


o 

e 


a 

•9 


*5 

HH 4J 


•NHUJMHOOOCO 

4 r-H M r-H r-< M r—< *—■< M 


NOOOiDCOiO't’fl' 
HHNH t-<* M* 1 -J 1 -i <M 


tPMcONOMiOOtP 

HHciHHClHOW 


rPOOOinNONOOO 

hhhhhNhhh 


COHinOHNHMt'- 

rH<MrH<M<Mi-HM<M^H 


JCOiCN^DNMOO 


ri'i'^PrpTprPTpiDLOTp 


TfO’tMCN’J'OiO 

in rp «ip in in in in in rp 


MOMOOOOOM 

iniOCCiO^'tfiOrpiD 


CO‘iOMOhOhOM 

rpiD^p^fioinin'iiin 


NrPM'cPMrtOlCH 

^lOiOKJiCiOiDiOiO 


1 

•9 

CD 

<D —« 

0 *3 
<D > 

Chro¬ 
nome¬ 
ter No. 

1841 

in co h rroocoMco 
cr. rr co hiococccn 

M CO M* M* M <M O »h O 
CO 00 00 M M M CO CO CO 
MMMCOCOCOCOCOCO 

CCOIOOOtPtCNN 

COCOCOiOl-OCOlOCO 

TP CO TP w M Tp ci CO TP 
OOOCOCOCO^rrrr 
MMMCOCOCCCOCOCO 

oooorrcoioooo 

hOtphmtphOh 

ocococoocoooo 

O 00 OC M <M CD CO CO tP 
M M M CC CO CO CC CO CO 

•■=. <D 

CD +3 

.9 

’o 

o 

Chro¬ 
nome¬ 
ter No. 
1833 

OrTOMt^Oi—COM 
co oco o co iO o ^ o 

c co6o6®cDcDNioin<6 

1" N N rH - H N W N 
M M M CO CO 00 CO CO CO 

OMMiDtPOLoOtP 

TPOMH03HWIOTP 

HHoioococoN 

0500 CD CO M CO TP r- 
MMMCOCOCOCOCCCO 

OOCC'TPTPCOinCDM 

rTT-HMI^U-COOMM 

N CD <D TP TP 1>I TP Ln N 
00 CO CO M M M CO CO CO 
MMMCOCOCCCOCOCO 


Yl’J'iOiC^MOOHD 

"HMOOiflMTPCOHO 

CO. 

f/)DinTPMHO5C00000 


rv'finU'ODrP 

^ooMoccmD, 
^t^COOOOOOOOOs 
CO M M M CO CO CO 


l/|OHNHincOD^O 
^ co ^ co m co tp in co cn 

GT|COi-OTtiC5t^i-OCOCOCO 

jOOO’pTPi'iDnio 

^cococococococococo 


(f ^MN'OrPNlNo 
^DMCDOOtPCDHh 

co. 

(/jCOTPCDOCOC 5 COM 

^OOOOOOCO^t^ 

^cocococococo'Tj'Tr 


en 9 

o.2 

CL 


. M , .CO . . Tji . 

• I • . I • • I 

—ihM M M CCCO CO tP 


.05 . . 

OC 00 05 05 




fiRnaflBCfiP 

c 3 c 3 c 3 ^ ^ c 3 o 3 


OOOOOOOOO 

CD<DO<DO<DOOO _______ 

Pfifi PflPfiPfiflfiP 


M - • lO • 

M • - M • 1 M • 

MMMMMMMM 


OTc3^c3<^c3c3c3o3 

^5 H} h; l-s I-) Hs hj l-i 


c*i Q5 


05 


lobi. 

00 0)03 03HHH- 


"3 "3 "3 ’B 1313 "3 3 

H H 1-5 ^ l-s H: H) 


OfiOfifififiPO fififififififipfi flfiflflqoflftfi ROfiOfiROfifi QfifififiRfiac 


2 i d 
o d S 


TP’PTPLOiniOcDOcD rr rpi i.o iO lO CO' O rp f rP in m m CO CD CO 

WPQ W WfPPQfPfflW KcqpqpqpqmMpqfq pQpqpqpQ.capqmnp; 


<i< rp ^ m in in co cd cd 

pq pq pq pq pq pq pq cq pq 


ipTPTpminmDDcD 

<1 *4 <1 *< < < *< 


bn 

.9 6 

££ 


INC0TPIOCDNCCO5 H M CO Tji lO CO 00 05 


< N M TP in D N 00 05 


HMC0TPincDN00O5 


HMMTPincONOCO 


o 

l> 


€ 

T? 

a 

c3 

c 

_o 

4 -i 

cc} 

- 4 - 5 > 

03 


so 

•g« 

o 

'd© 

O l”5 


CO ^ 

»-i o 

<M gf ? 
o^RPh 


<s 

o_- 

.-'3 
3 ts 

> o 

Oft. 

p . 
■P 

. o 

O »-a 
£ 


a_. 

r cJ ^ 
"o fe 

Cd O 

°p 
*d a 
?3 A 

. o 
O H> 

53 


r.“ o 
o-e.d 

<'■ »Ot? 

P | ® 

O t> 

s^Sa 

o dO o 

■&*>.£ 
du© o 

11^. 


J-jU 

o . 

.'do 

oS«r 

O o 

q “5g 

o O 
. • 
bo >>H 

.g-g ? § 

a § C S 

tn o 3 


July 11.1 413.33 













































































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY 


1G7 


M rH 

Pg 

© 
‘O © 
M O 


is 

© rH 

CO O 

to © 

X © 

■*T O 

85 

C5 Tl 

85 

05 H 


85 

05 •• 

o © 

X _ij 

05 H 

© O 

X 41 

05 11 

CO N H N *f CD 

O O rH i— ■ 1 1— ■1 •—1 

OHvcocoir 

C$ <3 C4 <S N S 

'(NN(N 

> to to »o 
INNN 

40HC005C505000 
CO CO CM M CO CO CO CO CO 

xxxxxxxxx 

CDtCONOONONH 

XXXXXXXX^r 

tO »o to tO «o to *o to »o 

V'rOOCJHtOiOiOM'f'V 
0D00MOCC05 00 00 X 00C0W 

o © © © o © 

DO GO GO 00 00 00 
05Q5C5 05 05C5 

05C5050JC5C5C05C5 

ooooooooo 
oc oc oo <x x x x x /. 

05 05 05 05 05 05 05 05 05 

ooooooooo 

A A A A (A A A, A. X 
05 05 C5 05 05 05 05 05 05 

OOOOOOOOOOOO 
X X X X X X X X X X X X 
05 05 05 05 05 05 05 05 05 05 05 05 


tCNfNHOOOOON 

r^oocj»oeofOcONN 

*■) « W CD CO «-- — — 

• "0 00 CO o c 
*) 0 ( 

. JOC _ _ _ 

3 40 tO »0 tO tO i-O 


co co c 

X 00 00 <__ 

88888 = 
to 40 *0 iO io »o 


WDWOCOO (N W 

OIC'I-hD.NNWWW 

© © © M M C- 

-- 00 CO CO C 


88888 : 


; 40 to O 
>888 


40‘OtOtO»OtOtOtO»0 



8888 


40 40 to to *o to *o 


joO’T’T’rHaco 

M X X »0 tO tO M rH rH 

!-• 1^ N 40 to to »0 *0 to 

888888888 
40 to to to to to to to to 


NCOIOOIHNOOOCPNOO 
(N (N H O N CO (N M CJ « W CC 

O'T'tcOcOcOCOCCCO CO C- 

I". tO to 40 »o t* ■ ‘ 

8888888c_ 

40 to to »o to to »o tO to » 



1838 
. 5008378 
. 5008388 
. 5008388 
. 5006654 
. 5006628 
. 5006631 
. 5006259 
. 5006278 
.5006282 

3477 

.5008391 
.5008394 
.5008381 
.5006267 
. 5006273 
.5006266 

1838 
. 5008033 
. 5008021 

.5008010 

.5006273 

.5006275 

.5006272 

.5005923 

.5005923 

. 5005921 

. 5007802 

. 5007825 

.5007842 

. 5006071 

.5006056 

. 5006063 

. 5005706 

. 5005721 

. 5005722 

.5007286 

.5007304 

.5007309 

. 5005552 

. 5005543 

. 5005548 

. 5005219 

. 5005193 

.5005173 

.5007431 

.5007429 

.5007409 

.5005670 

. 5005674 

. 5005663 

. 5005322 

. 5005326 

. 5005322 

. 5005334 

. 5005328 

. 5005339 

1836 

. 5008373 
. 5008386 
. 5008397 
. 5006648 
. 5006644 
. 5006630 
. 5006276 
. 5006275 
. 5006263 

1838 
.5008397 
.5008387 
.5008382 
. 5006267 
. 5006274 
. 5006269 

1828 
. 5008022 
. 5008022 
. 5008020 
. 5006273 
.5006273 
.5006272 
.5005922 

.5005921 

.5005922 

. 5007813 

. 5007820 

. 5007820 

. 5006089 

.5006054 

. 5006050 

.5005710 

. 5005722 

. 5005722 

.5007304 

. 5007298 

.5007300 

. 5005545 

.5005549 

. 5005550 

. 5005207 

. 5005193 

.5005195 

. 5007423 

.5007423 

.5007421 

.5005668 

. 5005668 

.5005671 

. 5005330 

.5005330 

. 5005329 

.5005330 

.5005330 

.5005321 

OOOOOOOOO 

1 1 1 1 1 1 1 ! 1 

x x X X X X 

1 1 1 1 1 1 

to to to to to to O to ‘O 

1 1 1 1 1 1 1 1 1 

u- r>. ih 

1 1 i i 1 1 1 1 1 

xxxxxxxxx 

HHrtHHriHH 1 —( 

1 1 1 1 1 1 1 1 1 

xxxxxxxxxxxx 

1 1 1 1 1 1 1 1 1 1 1 1 

GO « 

2HHH000 05fl5C5 
W It- If If X X X f ic T 
GOrrrr^Tfi^TTiTjimTr 

H+++++++++ 

f ' X X 00 05 ® Q 
r* x /j x «v ^ *r 

^iCOWCOif'f ^ 

co H—1—1—1—f“ 

2o(C<0C5 03 0iM*i- 
CO'rf’-"---*?,TrTCOCOX 

qt to »o to >0 to tO to to tO 

T-, + + + + + + + + + 

COXXNNNO®® 

-T-T''TXXXXXX 

'rrf’r'T'r'tififrf 

h— i—^— 1 —^—i—i— 1 — 

cOCOCOtflWtONNN 
|Q 4Q <Q CO M CO - if if 

MMMCOCOOOOOOOO 
COO OCC05C105QOSOC5 
if^^XXXXXXXXX 

++++++++++++ 

^iDiOiOCUNNifrfif 
Cv rH *-4 rH 

2 1 i|| 11 +++ 

52 x x x i-t i-h »-t 

“ncocoif ^ 

* cc CD CO CO CD CO 

*h 4* “1" + + 4“ 4- 

cv TJ 1 Tji to to to to *0 tO 

5 1 1 1 1 11 1 1 1 

iOtOIO*ct , ^f^T , ' - 7''7"7' 

XXXXXX<M<M<M 

1 1 1 1 If 1 1 1 

1 ^- r- 0 0 0 to »o to 

MM <M XXX XXX 

1 1 1 1 1 1 1 1 1 

CO<OCO»OtaHHi-IHHCM 

M<MMMMM<M<M<M<MM 

1 1 II 1 II 1 1 1 1 1 

CiOOXiOMMONCO 

2 NIC00 hh 

t'-oot^xr^rOXX 

X 1- t- T M M T-H O O 

rfHOOlO'flfNH 

HOSlOrtMH'JlfJlOlfTr 

r-H 

+++++++++ 

++++++ 

+++++++++ 

+++++++ 

++ ++++++ 

++++++++++++ 

05^0 05 WtOOStOrH 
N CO M tC iO CD L« X 

COCOCOCOCOCOCOCOW 

1 1 1 1 1 1 II 1 

OilOCCfiHH 
COOOQNtC 
CO X X (N CM CM 

II 1 1 II 

HCOl'OJN'fHOtO 

_*rtH<NXXiOCO»0 

777777777 

tO © X O O O b- -7 
X c5> to N CD LD I- to X 

M HrtHHrHHnH 

1 II 1 11 1 1 1 

OOCMCOXXCXMO 

OChOiD-COCDrfiOtr; 

+++++++++ 

MWHDOf OhO)NCh 
X' r'I’iOCDtCOCOVfrfCO 

»-H rH H r—4 rH rH rH rH rH 1 —4 1 —H rH 

1 1 1 II 1 1 1 1 1 1 1 

© M © -h r- iNhhh 

1 11 1 1 1 1 1 1 

O O X M M M 

1 1 1 II 1 

1 1 1 1 1 1 1 1 1 

h®OOhh®®® 
rH hhhh 

1 1 1 1 1 1 1 1 1 

hO®00h®N®® 

rH »—4 *—1 

1 1 1 1 1 1 1 1 1 

2 S 2222 SS 2222 

1 1 1 1 1 1 1 1 1 1 l 1 

1838 
. 5008277 
. 5008295 
. 5008295 
. 5006539 
. 5006518 
. 5006526 
. 5006191 
. 5006218 
. 5006229 

3477 
. 5008320 
. 5008321 
. 5008309 
.5006116 
.5006104 
. 5006078 

NO^O^ONCOh 
( f OOSOCNCiftCtC 

rz co co to x x x to 0 to 

CCr^r^t^toiotoio ir:> 

288SSS88S8 

“ to »o to to to to to »o tO 

. 5007599 
.5007576 
.5007562 
. 5005817 
.5005801 
. 5005792 
. 5005459 
. 5005452 
. 5005433 

.5006950 
.5000980 
. 5006983 
.5005256 
.5005259 
. 5005263 
.5004949 
. 5004921 
.5004893 

.5007178 
.5007179 

.5007157 

.5005444 

.5005454 

.5005437 

.5005109 

. 5005109 

.5005094 

. 5005104 

. 5005098 
. 5005094 

1836 
. 5008718 
. 500S739 
. 5008750 
. 5007015 
. 5007016 
. 5007007 
. 5006643 
. 5000650 i 
.5006645 

1838 1 
.5008081 
.5008070 
.5008065 
. 5005924 
.5005913 
.5005889 

HtOOONJCOO 

f/lOJOlXCDNOM-Of 

TT T—< rH rH Hi rf' rf rH r—< rH 

WXXXCDCDCOCOCOCD 

2§§SS8SSS8 

^tototototototototo 

. 5008093 
.5008054 
. 5008023 
.5006306 
.5006270 
.5006250 
.5005926 
. 5005916 
.5005896 

. 5007251 
.5007257 
.5007257 
. 5005514 
.5005530 
. 5005530 
.5005214 
.5005198 
.5005192 

. 5007598 
. 5007601 
.5007597 
.5005867 
.5005873 
. 5005870 
. 5005528 

.5005524 

. 5005512 

. 5005511 

.5005511 
. 5005487 

11? CD CO O N CO CD CO CO 
to to to O CO to ID 115 

f NCiOWf* 

to to ‘O to to to 

t-xxr^oox—4 -h 
tO *0 40 tO O CO tC CD O 

©b-X©MMX-7-7 

iCDtCCOCOCOCOCDCO 

00NXCOX®®HN 

OcOO»OtOtOtOcOO 

Xif ^f©HNMXX®®0 
'D tO <0 ID CD O CO tO t-O <0 tO CD 


tc N CO W O N O *P O 
00 05 O CO ^f 1 ^ 00 Oi rH 


- t'-t^f'-XXXXXX OOIOOOOOOOOOCOO MMMXXXXXX 


i-HrrWNOOCOCCOOtOiO^f 

xxxxxxxxxxxx 


OOH 00 05 H 05005 0 0 10005 05 

f-H oi rH i-H oi r-i oi 1-5 M rH M M rH rH 


C50C500050COX5C5 C500*H«5C0500CiON OOOOO^NtOOh-CC COHOOOCiOOOOOOONOOOO 

HeirHHHOiHHH HHINhNhHHH Mi-HrHrHrHrHMrHrH HWho5hHHHiHHHH 


x©*-7MMt^xx-*f ccoo cocoo 
40 40 to to to to tO »0‘0 to to 40 40 to to 


to N O N05 n 1 CO (N OhhNMWHOh (NCOhhI^MOOCH 

40 to to -Cj5 rr to to to to to to *c5 to to to to to to to 40 to «C ‘6 to to to to to 40 to to to to to to 40 to ‘6 •© 


^toxoxooxtox 

nr)NHHciTfc 02 <ojH 

ZLOOOXXXOOO 

^coxxxxx^^^ 

»^XXcDOX-r 
O O X X 0 x 

rH O O rH CO O rH 

Z OOOO rH rH 
x CO X X TT rfi rr< 

rf\ -T MCONf COtON 
^HfHHHifHMOO 

05 ..••••••• 

(/©ffiONCStOHOO 
M M X M M M tO tO *0 
r 1 XXX75f1f , -J , Tf , f 

MOMOOt-OOO 

tfiiOHCOVHXHCD 

© 6 hChNo 6©6 

MXXXXXiOtOcO 

XXWTflf tTfTf7 

XtDOXMO-fMHi 

HcOtONCO'fCOtO'f 

Q 00 00 CD tO 16 »0 X H 
O to to r- r- NQQh 

X X CC 7 7 7 >o 0 to 

X7C7C7tONCNOOcO 

MrCOI.QHNNXMXM 

OOXoic7io6c5c5CrHOOrH 
7 rf 7 10 LO co X X 05 C 05 Cl 

WXX7 7777777TT 

COl^eOMMOMXO^ 

SMiOMOXXX^t- 

CQ 

X^OOOCOt ^.000 

^OOCOCfit-OtOiONNN 

^MMMXXXXXX 

1838 

X X X •-< M M 

X M rr >0 X O 

© 6 6 oi co to 
(N c4 !M 

X X X T rt» 

f /1 N tD ® 00 CO if I'r CO O 
X; [' to N Tf tr Cj O GO X 

OQiOiOtONCOONON 

^OOOXXXOOO 
^XXXXXXrr ^ 1 ^ 

OOOTfXOMOO 
r © H ® M 0 V O if 

OOMCOO>OMX”'‘ 

OrHHOSOOMCqM 

XXXXX'Ti'^T'^'T 

OM©VMCN(OCO 
XO ©OCDCOQ7© 

lOiO'TCONC'iOHH 

- -T H 10 10 lO N X X 

XWX77V777 

7HQONNCC'D(NOOtOOO 

lO7<0lOH7CClCHHrtC 

a©©c6cOCDNM7776 
M M M M M M tO tO *0 »0 tO tO 
XCOC0777777777 

July 21. 

July 2)-22... 

July 22.. 

Julv 22. 

July 22-23... 

July 23. 

July 22. 

July 23-24... 
July 24. 


Sept. 5. 

Sept. 5-6_ 

Sept. 6 . 

Sept. 8 . 

Sept. 8-9_ 

Sept. 9. 


Sept. 16. 

Sept. 16-17.. 

Sept. 17. 

Sept. 17. 

Sept. 17-18.. 

Sept. 18. 

Sept. 18. 

Sept. 18-19.. 

Septl 19. 

Sept. 22. 

Sept. 22-23.. 

Sept. 23. 

Sept. 23. 

Sept. 23-24.. 

Sept. 24. 

Sept. 24. 

Sept. 24-25.. 

Sept. 25. 

Oct. 2. 

Oct. 2-3. 

Oct. 3. 

Oct. 3. 

Oct. 3-4. 

Oct. 4. 

Oct. 4. 

Oct. 4-5. 

Oct. 5. 

Oct. 8 . 

Oct. 8-9. 

Oct. 9. 

Oct. 9. 

Oct. 9-10.... 

Oct. 10 . 

Oct. 10 . 

Oct. 10-11... 

Oct. 11. 

Oct. 11. 

Oct. 11-12... 
Oct. 12. 

fipfloapopfi 


ppppafi 


RRRPPPPPP 

QPtfPQQaOjRP 

RPRPRPRRP 

RPPRPRRPPRRR 

tt to to >o co co co 

<j <i <<;-<<; <1 <! 


Tf Tf r^COCOCO 

<j <!<!■< 


rf7<rfiOtO*OCOCOcO 

Tfi Tf if tO O to CO <0 co 

<!<<•< < ■< <C <J •< •< 

rfM'TpiOtOiOCOCOCO 

< < << <1 

777iOiOiOCOCOcOCOcOcD 

rHMX^tOOt^XOi 


1-4 M X O M 

rH iH »H 


HNX^f iOCONX© 

iHMXTTtOOt^XO 

i-lMX^tOCl^XC 

hN«7iOCONX®OhN 

Washington, D. C., 
Coast and Geodetic 
Survey Office, C. L. 
Gamer. 


•7 o> 

0 e 

0 a 

1° 

!h 

id 

cS *-» 

rH . 

Zi 


No. 126. Bridgehamp- 
ton, N. Y., C. L. 
Garner. 

No. 127. Chatham, 
Mass., C. L. Gamer. 

No. 128. Rockland, 
Me., C. L. Gamer. 

No. 129. Lancaster, 
N. H., C. L. Gamer. 


S§ 

rg 

.O > 


3-g 

•H O 

OT w 

fl v 

° s 

ot »rj 
p+a 
•2 <*> 
.»_> c3 

£ 05 
CrC 
<X> H> 
CO . 

£ O 
O «5S 

a-* 
5 C3 

O Q> 

1o 

§*> 


£3 

l! 

"*n o 
2 % 

£ £ 

o o 

» o 

Q> C 

4-> Im 

CSX 

p-C 

© -o 


c Rate correction determined from comparisons with Western Union time signals. 
























































































































Pendulum observations and reductions —Continued. 


168 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


d 




S o 


o o 

00 II 
C5 it 


COO 

OO 

CO _M 

a> 


o o 

CO 44 

<y> -n 


1? 


o o 

CO 4| 
05 II 


COrHOtOOOOOOrH<N 
fo<MCCCO<M<M<MCMCOCO 
<rrr wrr’r^r 

S>© d o d © d © © d 

rvOCiCOOCOOCOOOOCOOOO 
H05 05 05 0505C5C50505 


OCOOCJCOOONOOCO 
t'- I- I'- NNNNCOO 
cocococoeococococo 

dddoddddd 

00 00 * 00 00 9 CO CO 00 

05 05 05 05 05 05 05 05 05 


ooooooooo 

COCO'COCCCOCOCOOCOO 
05 05 05 05 05 05 05 05 05 


ooio^oa>Mo^ 

to -r? to IQ «o «0 ‘O HJ« 
<M Ci <P\ <M Cl CN CM CM 

ddddddodd 

OOCOCCCOOC'COCOCOCO 

050505050505050505 


Hl'NC’-*OCO T f 
OOI-^t^COGCGCI-t^ 
CM <M <M CM CM CS CM «M 

ddddddod 

oo OC' oc cc 'CO co cr, oo 

05 05 05 05 05 05 05 05 


□ 

3 

© 


.-•^ecCCNCMUOCD 

iCiCO*OOOOTprj">r 
• N I- t’. LO tO to tO tO to 
50 0 0000000 

ooooooooo 

to »o to to »o to to to to 


OOOrPCMCOtoQG M 
OiMHtfjOtCOMM 
h-NNOSOOiCDCCCO 

pr to »o to »o »o to 

O OO O Q OOoO 

ooooooooo 

to to >o »c »c to to to >o 


_i t<- Tf Tjt CM (fI So K 

to^’^t^t^t-'i^eoco 
N N N to to to to to ‘O 

8 00000000 
0 0 0 0 00-00 
tototototototototo 


CDTf<H(MOOOCOO(M 
(M CO -h N CO tO O M ^ 
000(M<MC^C5C505 
CC CO X 0 CD CD tO tO tO 

8 00000000 
OC'OOOOOO 
tototototototototo 


CDOOcDCD^COOt^ 
’f lOiOOOCiQ'D 
05 (35 05 CM CM (M CC 00 

t- I- NCCCCC tjp 'O 

S O O O o o o o 
o O O o o o o 
to ‘O to to to to to »0 


'd 

o 


ft 


R 

o ^ ^ 

O M GO 

t- © —J 


M'CDNCCOMDCN 
O CO O CO CM CO 30 O to 
tO >o tO 00 00 OO 1* -T 

• t- r to to to to to »o 
oooooooooo 
ooooooooo 
to to to to to to to to »o 


^10000000050510^ 

cr w cc 'O cd C5 ^ co 

O l— l" 05 05 05 to O CO 

N I" l- to tO *0 *0 »C to 

ooooooooo 

ooooooooo 

tototototototototo 


ocycoio-n’o-ii—<(Xco 
iOrrrjit>-l>-t^-Tt'COCO 

t" to to to to to to 


tototototototototo 


O CO CM <M 00 <M M t'- -rf* 
COiNrHNNCOi-iCOeO 
000<M<M<M05C305 
OC CO OC O CO CO to tO tO 

888888888 

tototototototototo 


<N(MNO0N«0 
tO CO »0 •—i O 05 to CO 
05 05 05 CM CM t-« OC CO 

t'- I — CO CO CO tO to 

88888888 

to to to to to ‘O to to 


a o ~ 

O MOO 

s ® 


CdO-^r-iMOOait'O 
I'OecOMNOCr- 
to to to CO oO CO T -r nr 
• I- L- to to to to to to 

<>50000000 00 
000 0-000 0 0 
tototototototototo 


I O O to to O rH C l CM 
NGNCOcacOO'D 
l> N N o o to to to to 


tototototototototo 


05 0500Tr-rt*(Mc^r«-r>- 
-r Tj« N N NCO CO 

t>- I - to to to to to to 

888888888 

tototototototototo 


mhChC!0ioCcC5 

Dlrjir-NCCtOCM^ 

000<M(MCM050505 

00 CC 00 CO CO CO to to to 

888888888 

to to lO to 1C to *0 to to 


5 —I TT CO 00 
> O 1-1 to © 
I CM M (X CO 
5 CO CO IT - “ 


C5 Tf 1-1 C 

CC to cc c 
c; 05 05 5 
r- r- c 

8 000OOUO 

o o © o o © o 

totototototototo 


c3 

ft 

73 

B 

I 

'd 


§ 

i 


□ 

o 


o 

O 


© 


Is 

ft » 


A 

H 

i 

FI 

M 

.GO | 
OM 

g 

o 

d 

© 

1 

4 

A 


.00 1 

H 

a 

© 

O N 

O 

o 

d 

4H 

© 



cooocooooooooooooo 


I I I I I I I I I 


OOOOCOOOOOGOCOOOOO 

I I I I I II I I 


0505050505 05 00505 CM CM CM C5 <M CM CM CM CM ©COCOCOCOCOCOCO © 

HHHHHHHHH 

I I I I M I I I I I I I I I I I I I I I I I I I I I 


03 


000O5O5OO5OO5 
00 00 00 C5 05 O CO CO CO 
MCMCMMCMCMMCMCM 


CC M CO H rH r-an lO to 
05 05 05 CO CC CO <M CM CM 
CM CM CM CM <M CM CM CM CM 


+++++++++ 


3 tO to to 

r-l r—l r-» r-l rH rH rH rH rH 

+++++++++ 


I II I I I I I I + + + + + + + + + + + + + + + + + + 


++++++++ 


+ 

m 

+ 

83 


II 

ft W 


tOVCOO^^ COHO to COM IO COHIO-^CO O CO to H TTCO to CO 0 H Tf to M O to ’ 


+ + + + H- + + + + + + + + + + + + ++ I + 


+ 


CO O H 0 to CO ^ 


+ I+++++ 


£ A £ 

® ® 3 
H ft 4 ^ 


OrtH©000505 


+++++++++ 


O^OOhco^OCTi 
iO’>fiOiO‘OtOtOLO'5i 

+++++++++ ++++++++ 


4 O O O O 05 o rH rH <M O O rH O 1-4 05C5C5005 1H05NM H005-<05 05f 


I I I II I II I I I I I I I I I I I I I I I I I I I II I I I I I I I I I I II I I I I 


d 

d 

'd 

o 


r GO 


9 o - 

o ^ 

§z« 

5-Sh 

O® 


WO0O0 
HCO0r-Or < cOO 
»T3rCO00OCOCOCO 
• N N N iO tO tO tO tO O 

=888888888 

tototototototototo 


NO^^MHrrOCO 
N r-O Tf tO CO H tO 't 
CO^'fOOcOCOCOCO 

to to »o *o to to 

888888888 

tototototototototo 


MOtO^MHfHOO 

ON^MCO'VOCOJ© 

'tCOCO0»OtOM'Hr- 

NNNOtOiOiOiOiO 

888888888 

tototototototototo 


S CO C) CO M CO C C O 
rH C5 rH CM CC to C5 CM 
rr CO CO CO tO <M 05 OO 
N N N iQ ‘O tO tO »C tO 

888888888 

tototototototototo 


05 ^0 05 Tt* 05 05 

iO 0 0 h C C 0 N 
NNNOCO00 
N N N 0 0 0 0 tO 


tO tO to »o »o »o tO »o 


o 

1 

to 


3 o — 

O wco 


to 05 CO' -H r- rH CO 05 -rr 

cm o cr. co to to co t co 

N00OO5O5000 

• S N t-' o to to to to to 

*888888888 

to to to to to to to to to 


0HC)0O^N0O5 
05 tO' CO <M CO CO 
COCC’OCC'COCXtOtOtO 
N N N 0 iC tO »0 0 'O . - i - 

o8ccsSc88 §8 

tototototototototo --- 


•Q'ff'rf 000COM» 
NNN to to to- to tO to 
OOOOOOOOO 

ooooooooo 

tototototototototo 


OOCCNHO-HIOON 

OOMXOH0CIOCH 

CO r t'CC00iOMMCC 

r-u- »o »o *o to to to 

888888888 

tototototototototo 


co-^TTcrooc_ 

oiWOOCCHNN 
N N N 0 0 O tO iO 

g o O O O Q o O 

O O O O O O O 

totototototototo 


3 2 
m g 
ft W 


JCOOhoOCOhCOM 1 

§1000000000 


30tOCOtOtO0tOtO 


0O00 WO50MOO 
000000000 


COOI"OCOCO»OCOO OO0N00MMO H 0 t}i h h 000 tt D) 0 05 M M 0 0 O 

CO O 0't' w M M M H ^l-^O5CON0HC*5 Of-lOOt'-rH'-rOOC^ 0 CO <M t? 0 0 N 00 05 

^^COCOCOCOCOCOCO COCOCOCOCOCMCOCMrH dcodddddcMOO CM CM CM CM CM CM 05 oi Ol 

— 1 rH »-H rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH rH 


03 

08 

HH) 

o 


S22 

® © d 
H ft 4 "* 


,^H- r <HH , OOt0OO 
0CONtO*r rH CNO 

0 L-I t-1 I'i t- f- 00 00 


C3 

1 


jJC005C5t^C50C5 0000 


0505005051^-05 0500 

HHHHHHHHH 


NH05 050C0 05C5 05 

H M H H M rH rH rH rH 


00 00 0 05 05 05 rH CD 05 00 t-05 00 00 05 CO u- 

HHHHHHHHM HHHHHHHH rH 


a 

© 

OrH 

a os 
© > 
■d m 
© 
O H-» 

d 

o 

O 


IO tO 0 0 0 0 0 0 0 


H'TJ'HIIOMNNOH 

000000000 


MH'M^HNMHCN HHOWO50OOMO5 

tototototototototo to to to to ■'f to to ^ 


NNOtCOOI'CO 
to to to to to to to to 


A 6 OX 
m gx w 

rd g'TCC 


<c | . 00 00 rH CO CC X M H 
COMCOTTHCDOt^ 
cococct' r r-T'T'T'-r'*r 


CNOOWM^ONOO 

COCOCO'^'^'^t't^cOCO 

cococo’^-^Tr^Ht'^ 


OOC!O^OOhcCh-»Ji 

COCO-^TfrriO^-OOOO 

coeoco^^M’Tr’TT'-j’ 


CO 

d 


A a>,°00 
5 gx« 

3=Ot.® 

<J a 


© 

4H 

03 

Q 


II 

Cu +» 


Si| 


c CH00O>QpWW’t 
CM CM <M rt CM CM 'f -'T — 
cocooo-rM’Tj'rr | r?«rr' 


0MO0N0COCOO 

COTPC5COCOOOOOOO 

000000DlMrH 
M M M M M (M 0 0 0 

coccco^^r^r'^^^ 


5 0 05 C tO 05 r 

CDcDNOMtcddci 
CD CO CC Tt' rr 1^ t ' OO 
0 M ^ TT 


00^000 0005^0 
cococc T t' , ^ , 0t^r^N 
cccocc'^V'rr'^r^r^r^ 


- _ ^ — OHNNCOVOtQ 
^ O O U- NCCHOO5OCO5 0 

005C5 1H005MM 

hhhhhOWW 

COCOCOT^HjlTr'Hf'^ 


Zh d t-4 cc d ci n r- oo 

05 rH rl rH rH rH rH rH rH rH 
rH •■••••••* 

OOOOOOOOO 

OOOOOOOOO 


• CO 

to t(i CC CO 


00 

r-^ oo 


>>>**>>>>> 

ooooooooo 


>>>>>>>>> 

ooooooooo 


cc • • Hjt • • to 
CM • *05 • • M 

04 cl| MMCOHi ^410 
CM <M C'l CN M <M M <M 04 


>>>>>>>>> 

ooooooooo 


8 


• CO 


500 . 

. . . 

>■>>>>>> art 6 

O O O o o o o <-* a> 


OPQClQfiQfiP fififiOQORQQ PpPPOPfifiP RQflfiQQOfiQ QPOftQPQq Q 


Hf to tO tO CC CO CO TTTf<H'0IC000'0 ^TT'«'000000 H<H , T} < lC00 000 ■^H<^'0 0000 CO 

<5*<;■<^*<<1 <1 *<<j< 5<j*<< <^•<*<-tj 


Cuo 

.2 o 

m 


& 

o 

TJ 


d 

o 


c3 

H-3> 


IM Wrr 00NOOO5 


<MCD'J'00NCCO5 HNCO'O00NOOO5 rH<MC0^tOCOI>0C'O5 


< m co ^ 0 0 cc o 


33 1 *3 

03 § 

3 


3 

So 

ft 

r2' 




H-5 

d 

A 

o - 


2> : 



rH 


o 

Z 



B © 

Is 

u ~ 
£0 
C3 ^ 

*3 

co>C 


o 2 
ftp 

30 

OTP 

d^ 


CS 

ft 


. 

W c 

B 

03 

ttO 

60 

z 
















































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


169 


is 

© CM 
28 

xo 

05 O 

o -H 

S-H 


X CM 

© rH 

N rH 

as 

X o 

CM O 

© O 
CM O 

05 © 

05 O 

05 O 

s + 

S-H 

05 + 


05rHrnx©xt'-xx 

X QO C/D 05 X X X X X 
O © 03 O Oi O) 05 05 C> 

XXXXOCOOXXX 

n- n- n» n»n» n- f-» i**. 

05©©©©©©©© 


500l-TJ«XrHaig5©XXX 
COCOMCCxCCOOJNfiC'DN'M 
X 00 X © © CO CO © © © CD © 

0008S8S00000 

ICIOIO^CUOIOOIOIOOIOIO 


XXCM©'H 4 <NXX<N'H 4 XC 


05 03 O 05 05 05 05 05 05 05 05 05 
05 05 05 05 05 05 05 05 05 05 05 05 


OCCOCOOOOOOC^N 
tOC'COOHiOOO 
(M (M W © © i-h i-h rH 
rHrHrH©©©©©© 

0 SS 888888 

10 10 »o O 10 10 «o 10 


NOCOOOWWO^H^ 
©XG5XrH©XCM©©X05 
xxx©rHrHrHrHrHt>.t^t>. 
000^ 05 05 05 05 05 00 00 00 

000S000S0000 

I0i0»0i0u:i0ic»0i0i0i0i0 


rt 4 ©©'—'©©©,—(TfXrH© 

CNCNCNCI<N<NC1<NCNCNC1<N 

05 05 05 05 05 05 05 05 05 05 05 05 

n- t- r- i - t^- r- n- t'. t'- r- 

05 05 05 05 05 05 05 05 05 05 05 05 


■^C^t^CVJC0OTrrt*GC050CiC0 

V'XHOM^COiO^OOO© 

lOiOOOcDOOOCOCCi'tLO'V 

C O O O O O 00 00 00 X X 00 


10*-<0©1CNMOOH 

XXXXXXfXX 

C1<NCJCN<N<NC1<NC1 

050505050505050505 
n. t~ 1 - c- r- t - 
05 05 05 05 05 05 05 05 05 


HOH © CC’J* N *-< 
lO 1C >C C LO •(? © © o 
<NCN<N<N<N<NCN Cl CM 

05 05 05 05 05 05 05 05 05 
I- 1^ I— N- 1^. N- I-* N-. 

05 05 05 05 05 05 05 05 05 


<OOCOO©M<HON 
HNCO<O<O<COHCO 
©©©XXX©©© 
OOO 00 X X X X CSj 

00S88SS88 

© © >0 lO LO 10 10 © »o 


© «^<OCOW©<00 
I- O i' 03 o H <c CT; 
©©©i^xx-^-r-t 4 

ooooooococoocco 

oocSSSoco 

10 U5 U5 1C «5 »C lO Wj *c 


CO H X CO c 
H *0 GO r- X c 

nasals 

?8o8oOuuutiuuo 
^ 1-0 10 »0 <0 ICMO »o <0 10 10 »o iO 


^OJCOCOCOO^HLO 

® 'J'NNCOOHiON?0 
CM CM CM nf ‘O »0 rH »—< «-h 
fjHiHHO©©©©© 


OCNHi.CQlCNNQNOtO 
'f <Z H r/j o <C CO © <0 <C © 
OOOCOOhhhOhM^n 
0 00©©©©©©00 00 00 

000088888888 

©©©©©©©©©©©© 


« fH (M tc x ^ rf ■*}« © rH 05 
■»f 1 O<O<OO<OOOOOOOTP 1 O V 


000000 X X CO oc oc 00 

rHrHrHrHrHrH©©©©©© 

000000000000 

lOifJiOiCiCiOOiOiCiOiOiO 


ci x co co c 
*— co cm co c- © c_ 
<0<6<CCOCCOOU5»0>0 


-- . <0 0)Ohi-C 05 
LOICIONCOOO wrp 

oooxxxxxx 

188888 

) id © © to »o 


CM N H*H©rj«NNcD^J' CO N- 
MNCOOiONOCiOOOC 05 X I- 
1 ; X co X © © © CM Cl CM Cl CM M 

Kccooofototoocootooco 

*888888888888 

^lOiOiOiOiOtOiOiCiCiOiCO 


0CM*HHHCNC5COO5 

Yi1 , <D<DOihhlO<0<0 

^CNCNCNH 4 ©©*——<rH 
CM rH rH HC5©C5©©© 

JooccoSooo 

Wi0iC»C»0»0»C»0»C»f5 


NTfClCOiOCCOiOH^ 
D-COXNCMCOCO^'^'V©05 
XXX©THrHrHrHrHt^t'«.t'- 
0000 05 05 05 05 05XXX 
^H^H^-IOOOOOOOOO 

000000000000 

V3*0U5u5«0»<5V5i0i0iC»0i0 


©©wvchohococciom 

C5©<NXOC5CN©©XO© 
© co © © © © X X X TT © © 

ooooooxxxxxx 

00000000S000 

lOiCiCiCiCiOiOiCifSiOiCLO 


OCMCOrJ'mOCMH^ 

rH<NX©©t^OCMCN 

<O<O<OOOCOOC 1 O 1 CIO 

oooxxxxxx 

000S0000S 
to 10 LC uc LC LC »c »C >0 


iO<0«’t05Tf(CC3 00 
<0<0 00COHIO<0<0 
lOiCiOI^OOCOrrrfi* 
OOOXXXXXX 

<000000 

000000000 

I0»0u5»0»0i0i0»0»0) 


05 05 05 05 ©5 05 05 05 05 05 05 05 

I I I I I I I I I II I 


*, 


CO * , H * 


r 00 


I I I I I I I I I I I I 


CMCM<N<MCMCMCM<M<M 

Mil! I I II 

4 r-< rH rH 

! rH rH rH 

- + + + 


05 05 05 05 05 05 05 05 05 05 05 05 

rH rH rH rH rH HHHHHH rH 

I I I I I I I f I I I ! 


I I I I I II I I I I I I I I I I I I I I 


NNWN«NMNW 

I I I I I I I I I 


imoiooooopoioioio 

CMCMCM<MCM(MCM<MiMHtHrH 

+ + + + - 


XXXXXXXXX*. 


>© 

< rH 

■+ + 


+++++++++ 


oooxxxf^r^i'r 

<O<C<OCCX00CMC5C1 

hhhhhhCMWCM 

+++++++++ 


ft 

A > i '-1 
«t-1 


00 , 
w 

< *7 ^ ^ co 


I''* N N 1-H r—t fH r—( i-H rH X X X 


I I I I I I I I I I I I H | | I I I I I I I I I I | | I | | | | | | I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 


OONiOOOMOO^CliOCOH 

++++++++++++ 


HOON<OtO©MO OOOOOOWOIOVIOMCI lO^^iOCOWiO VCOOONO H00510C10C5 00N ©©r^^CNi-Ht^©© 

HHH rH HH 

+ + 4* 4- 4- + + + + ++++++++ + + + 4-_+ + + + 4- + + + + + + + + + + + + + + + + + + 4- + + + + + 


CMOMOOh<Dt}<hCM©NC1 

H10NN©OiC<0<0C0<Nh 

I +++++++++++ 

I II 1 I i MUM 


H X CO CM 05 05 X © X 
©NHCOX<CN©X 

CMWWHHrHHHrH 

II I I I I I I | 


O 05 <N 1 -H o * 


05iO<OOhOCCCtj<C 1N</0 
NNHNh*M03 0»OW'f<0 
CM CM CM i-H rH rH rH 

I I I I I I II I 4-4-4- 

■* 05 rH 


OOM<MMH©WN(»N»0 

»OlOtO<OCMW«HrtH 1-H 
CM CM i-H 


4" 4- 4-4- 4" 


III I I I II I +4-4- 


< X 1 -H CO 1 -H i—l r 


O i-H O O O i-H 05 r 


<i-H»*hOi-Hi-HOOi-H HHNOHHC5* 


II I I I I III I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 


1841 

.5008503 
.5008466 
.5008444 
.5006685 
.5006672 
.5006652 
.5006250 
.5006244 
.5006261 
.5006274 
.5006294 
.5005312 

1838 
.5011460 
.5011475 
.5011420 
.5009589 
. 5009616 
. 5009610 
.5009243 
.5009280 
. 5009203 

.5010891 
. 5010928 
. 5010893 
. 5009072 
. 5009093 
.5009119 
.5009047 
. 5009021 
.5009036 
.5008605 
.5008598 
.5008606 

.5010587 
.5010655 
. 5010624 
. 5010532 
. 5010538 
. 5010507 
. .5008711 
.5008738 
.5008716 
. 5008354 
. 5008400 
. 5008392 

.5010510 

.5010532 

. 5010533 

. 5008801 

.5008810 

.5008788 

. 7)008397 

.5008412 

. 5008439 

. 5010383 

. 5010383 

. 5010410 

.5008654 

. 5008690 

.5008721 

.5008313 

.5008347 

. 5008356 

cat— cjrtcc©3x<OXTfr'-x 

w>MNC0iOhNCC00C«Kit 
;; iniO’-NNCnc'i Ci x cc x 
Cv Ci- y.CC'OCtO’XCtOCtOC 
XQOOOOOCOOOCO 
^-OCCOCOOCCOCC© 
^101010»010101010 10>01010 

1828 

5011633 

5011636 

5011574 

5009764 

5009791 

5009773 

5009438 

5009465 

5009457 

5011223 

5011228 

5011167 

5009318 

5009368 

5009344 

5009304 

5009328 

5009271 

5008756 

500S7S7 

5008769 

5010950 

5010962 

5010888 

5010747 

5010728 

5010668 

5008882 

5008948 

5008928 

5008560 

5008603 

5008611 

5010755 

5010764 

5010779 

5008972 

5008983 

5008993 

5008603 

5008025 

5008628 

5010552 

5010581 

5010619 

5008895 

5008936 

500S968 

5008622 

5008649 

5008628 


IO<CNTJ<<0N<0 0CONC1H 
O <C 'O lO >C 1 C lO IO <o >o >o o 

XtJ*t}<NCCX»ON© 

10 I 0 »CICIC» 0 » 0»010 

Tf<0<0 00QOX©©XOH 

05C©X©©X05©C0CCI^ 

u 0 ©©iC©©iOiO©iO»O»O 

NWH®HWHlO<0 

10101010 ©©»C ©10 

©x©©r-^ci©r'X 

©©©©©©©©© 

©OiQlOCONiOO-tOON^ 

NXfiHOOTfWHH'ocin 

iOW»OTf OX>0»ON 
©<OHX»OOCM<OX 

NN»C>ONO<ONXt(<XN 

< 0 <OHOOHHTJ<NNXCO 

NNQX<DC00HHXX<O 

©0©H<ONO<ONIOHX 

00<OH<O00HH<DH 

^lOCOHfiXXXXX 

HHHXH©COHCO 

X©HCMXHNO© 

IOMWMWWHHHHHN 
rH rH rH ^4 rH rH rH rH r-H rH 1— 4 rH 

1 —< rH © © © © © 05 © 
CMCM ClHHrlrHHrH 

-HO©©CONN<OTt<XX 

NNNhhhhhhhhh 

©©CO©»C'Hirji-^'Hi^}iiouO 

NNHHHHHHHHHH 

© © © © CO © CO CO © 

rH rH rH rH rH rH rH rH i-H 

WWHLC 1 O<O<ON<O 

rH rH rH rH rH rH rH rH rH 

NXXOXCMOiXOOOiO 

0CNtJ<©XhN©© 

O © 05 CO 05 CM © 05 O 05 N- © 

©OHN©ON©HNX© 

©©H00©O0CNH 

rH©CMt^©0©05X 

i-HrHCMCMrHClrHrHCMCMrHM 

1 -HrHClHHCMHCMH 

NhhhhNhhNhhh 

hNNhhnhhnhhh 

rH H N H H CM H rH CM 

NhNhhNhhh 

lOiOiOMWOCiOXOOir-tif 

VHHCONCMTfMH 

XCMCMHTPOCMCOTfLOHO 

HMHNHNHMNNHiO 

CNXXH<NCNX<N<N 

XXXCIXCIXH 4 © 

|Q 1 C O 10 lO TT 10 >o >o »o lO *o 

ic. 16 io >o io »o io >-6 

loioioioidviioiooiooio 

UO»OiOiOiOiOiOlOiOiOiOiO 

©»o»o»/iio©ioioio 

to©©©©©©©© 

_^©M<OiOXC1©(M<ONCMO 

^Tj'XOTfrHco'n’d'CNO 

^iOONNOOONhh 

^J©XHjlCMHjl©©©Ttl 

W. 

(/iorx®Hoooc.o 

rH rH rH CO C© CC t'— CO f — 

^CJCICMCMCMCMCMCMCM 

<ONONNXH'N<OXCCH 

ONOOM<<OX<CHONO 

'H’C1CMX'HH«©©<M©CM© 

tOHOCOCNHiCCXNHH 

XX©©©X‘0©X 

COXX<ON©N<CN 

X N- © X © X 05 1 -H 

CMCM©XCMrHCM05l- 

aft + io© + *o©o©o>xt^cd 

^©©©Nl'NOO©©©© 

^CMCNMXXX’TfHjicOXXX 

6©0<DVOTjl<6NNHHrH 

MNCONNNNNN©©© 

CM<MCMCMCMCMCMCMCMCM<M<M 

COIOIONNCTNONOOCOO 
XXXXXXXX X 05 05 © 
CMCM<MCM<M<MCM<MCMCMC1C1 

CONNHHHCONtC 
X X X X X X © © © 
CMCM<MCM<MCM<MCMCM 

HrHOOOONnoi© 
HHHCOOOXO©© 
<MCM<MCM<MCMXCM Cl 

*v> ) T*i©i.0O , T*«05l^©i©X©X 
^hNOJOONNhhhhOO 
W •••••••••••• 

TOlriOOdTfNOOXiCiO'H 

30>05o>rrt*rt^oio5oi05©oa 

^CMCMCMXXXXXXXXX 

^ OiOOtONOOXif 
*TfXiOiO00XT)i<O00 

w. 

/Y-|*OlO©CO»OCOLOTrrti 
■^HHH10I0 10<0<0<0 
T^CMCMCNCMCMCMCMCMCM 

<C<OXO<C<CCHNHHO 

NHXCOXOHiOHOOtO 

rH»0»-4CM©©©©CM©©Tt1 

XiOHHiOXC©iO<OHX 

©<ON<OOH©OON 

©NHHCOiOOXN 

CM©CM©©©X©co 

-^^©©CMCMtj 4 ©^ 

XX + XNXO50C©©»O*© 
NNN<C<C<O<C<CNCCCCX 
CMCMC1<M<M<M<M<MC1CM<M<M 

XXOXX'HrH©©ClrH© 

CMC1XXXXXN-X©©© 

CM<MC1<MC1<MCMCMC1C1CMC1 

Cl CM CM 05 00 X h © © 
X<C^NNNClOCl 
CM<MCMCMCM<M<M<MCM 

N« © © rH ©' © © © —7 

xxxxxr-©x^. 

CMCMCMCMCMCMCMCMd 

• •••*•••••«• 

*•••••• CM * * CO * 

• » • t » t • (H ■ * rH * 

»o ■ x • • © • • 1 •• 1 * 

-H . I • • I . rH rH Cl Cl CM x 

©>t— trOOXXOli-Hr-rHrHr-'f-l 

:S ; jS j :8 ; 

NtloOOOOO©©^ © 

HHHHHHHHN 

,'«d \ lx* ! jo> j 

up CO © ci N-' nI x* X X 05* 

.CM . .Cl . .CM . .CM . 

TP 4« © »c »i co cd + N N-* N- X 
CMC1CM<M<MCMCM<MCMCMCMCM 

, X . , + . . © , 

• rH • «rH • . rH • 

cm'c^x' xx + + + »o 

rH rH rH rH rH rH rH rH rH 

i 05 , , © , , rH , 

. rH . , CM . .CM . 

oo ckoi © © o o i h 
hhhhhNNNN 

rtdofJcjdcdfjdcB 

c3c3c3c3c3c3c3c3c3c3ct3c3 

hbhh 1 —sbOhhbhh 


kn'(H 

c3c3c3c3c3c3c3rtc3c3c3c3 

saassssssssa 

OOOOOtOOOOOOO 

l_i l-i iJ K-i S-i f-i t-i t-i Ui 
c3c<3c3c3c3cic3c5rt 

aasssssaa 

(mI_.U.(h(h Ih U 

^C3c3c3c3c3c5c3c3 

aaaaasaaa 

oaoofiflacoaao 

OfiOfififiQOQ 

OflfififtRCfififlfifl 

cficnfiooficoofl 

OOCflflOflOfl 

fifiRflfififSfifi 

Tfuf^ioiOiOXOCOCOCO’OO 

«««««« 

rrrriTflOiOOOOO 

HHH 1 O 1 O 1 OIO<OO<C<O<O 


Hi H 4 tJ 4 1 © © >0 © © © 

<4 <<<<<<<<<! 

H 4 H 4 H 4 © © © © © © 

rHdXTj'LCCONCCOOrjOl 

ih«Xtj<IO<ON00© 

HNXHiO<CNCO©OHN 

rH rH rH 

hncoh<o<cnoo©ohn 

rH rH rH 

HNMHiO©N00© 

HNMH©©N0C® 


6-B^ : 

© • < 

.'do 

H 

sis 

d 4! 

bo . 

© . 

03 *- 
• - © 

> p 
§§ 

8 S 

W . 

MS 

. C3 

■S.O « ^ 

a^|l 

© 

go 

.3fe 

so 

®o 

So 

O • 

WiJ 

5E 

© 03 


1—1 , 
o 

o 

fl ® 2 

28&I 

© P 

E3 08 

*o 

Sdi 

159. 
a., C. 

160. 
a., C. 

© r 

2 o 3 j 5 
rfOMO 

©^ 

do 

oE 


o to 

& 

a 

a 


£ 


































































































































Pendulum observations and reductions —Continued. 


170 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


C3> 

a 

a 

© 




05 o 

S-H 


CM H 

© rH 

© rH 

CO rH 

© © 

© O 

©O 
^ © 

S8 

S8 

05© 

05©* 

05©* 

05©’ 

S-H 

05 "H 

S-n 

S-n 



a 

- 


COCOCOOOCMH<©00© 
<>5 'T f rf< iO iO rp iO’t' >0 

52r.© 05 05 05 05 05 05 05 05 
r>,NNNNt'-Nh*NN 
05 05 05 05 05 05 05 05 05 


*f tptpqOOCOCiOtJ' 

oo oo gc © i-h ro r- t- 

©OOC0C0C0050505 

• o © © oo oo oc 

’ooo 888 oc§ 

»C ic LO to O »C I 


5 © 


WHH©CO» 00 > 0 © 

©©©©©©H<©© 

©©©©©©©©© 

C5C505C505C5050505 
1 - l- h- l'- t- 

©©05©050505©05 


©©©©©©CM©© 
OC' 00 CO © © © l"» l"- t'- 

§ 05 © CO 00 OO £^ 

§8888888 

©©©©©©©©© 


©©^©OOt-rCCMCO 

O’r^©*cioo i oio 

■rhTp^TtlTt-TpTPTPTp 

C1C5 05 05 05 05©C5© 
r- tv. i - t- t~ i — i - i - 
©©©©©©©©05 


©©•^T^f^T^I^X 1 © 
H< t - U- 00 © © H< © © 
©©©CMCOC0 00505 
© © © CO 00 00 u- t- 

0008888SS 

©©©©©©©©© 


CO I''* 00 CO © t*- *-H 00 00 HfHN«J©NCOH© 

CO CO CO CO CO CO CO CO CO CO CO CM CO CO CO CO ’■f Tf 

© to to to to to to © to ©©©©©©©©© 


©©©©©©©©© 
{^. |v. i^. tv. t— U» t'* 

©05 ©C5©©©©© 


©©©©©©I©©© 

l v t>- N f- 

©©©©©©©©© 


00 00 c 


5 © ^ r}< 

, . 5 t - t>- 

5 GO GO *Aj u- 

_388 

> © © © ‘O O 


H<CMH<©©©©©t- 

©©^^©©©oooo 

©©©oocooo©^-* 

© © © tv. tv. t - 

888088008 

I0»0»010i0l0u5*0»0 


T3 

o 


<u 


9 «-» 

U£t* 

~ 0 


OCOhOtPO©©h 
CCCOOO©’-(^J'© t^t'^ 
-5 CM CO CO 05 05 © 

: oo oo oo r>- i- 

>8888 

5 to © © © 


• 888 c 


5 © t 


rHOt-cD©00©©© 
0—<0©»0^fCO©© 
ajOOOOOOCNOO 
© © © 00 00 co i"- r-. i " 
OOOOOOOOO 
000000000 
©©©©©©©©© 


_ .jNOOIU'CO 

©©©CMcoco©©© 

OOO 00 00 CO l- £- 

000888888 

©©©©>0©©©© 


CMCO©©*-lCMrH©CO 
o *p :c h © © t'- ^ rp 
COODCTiHOONNh* 

© © O CO X x 1 ^ t -u- 

088 SSS 888 

©©©©©©©©© 


CM©©rH©H*©f-v© 
O O h »}< f- iO h 00 
OcOOXXX©TPf 
© © © tv tv tv tv. tv tv 

888888888 

©©©©©©©©© 


§5« 

a z « 

o^oe 

Cj _ 
r* -h ^ 

e ® 


^HCOOO^-ii'-<MCOCOCO 

OOOOOOrHrHCM©fvtv 

S oocococo©©© 
OOOOCOXNNN 
■ ^OOQOOOOO 


© © © co OC' oo u- tv r 

08888888 c 

©©©©©©©©t 


OOCOOXNHIOX tvcO©©00©©©CM 

© O CO © © O to © co © © o to © © 

OOONNwap© 00 00 00 O O H l - tv tv 
OOCXXXN l — l— 05 © © A CO OO l'- tv tv 

000888888 80580 B 2 S 0 

© © © © © © © © © ©©©©©©©©© 


tv©©rHrHlvrHC 0 ' 0 < 

OOO©©©©©© 

OOOXXXTpTprp 
© © © tv l- tv L~ tv lv 

8 SSS 88888 

©©©©©©©©© 


o 

o 

C3 


oi 

a 

Q 

CD 

'V 

& 

a 

<D 


a 

o 


o 

o 


X CD 
CD t-. 

pCH ^ 


HHHHHHHHH OOCOOOOOOOOOOCOOOO COCOeOCOCOeOCOCOeO CMCMCMCMCMCMCMCMCM COCOCOCOCOCOCOCOCO 

rH r~4 rH rH tH rH rH rH rH rH rH rH »H rH rH rH rH r-H r—» r—i fH rH rH rH rH *-I r-H r—I i"H rH r—< i~l r-^ *-H rH 

I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I I 1 I I I 1 I I I 1 I 


« 


a o occ 


HHHtO©©©©© 
TP 'f-r CO CO CO rH rH rH 
NMNNNCKNWO 

H—h -f- H—I—I—I—I—h 


oooooocococot^t'-r^- 

HrHHXXXNNN 

NNNHHHHHH 

H—P "4—I—I—I—I—i—h 


+ + + + + + + + 4- + + + - 


HHHCOCOO'^COCD 
OOOOtCKDMCOW 
O) CM CM r 


- + + 


_J © C__ _ _ 

CN(N(M© 0 ©©©© 

+++++++++ 


-® 

J-CoOW 

go^^oc 


- 00 00 

1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 


11 1 1 1 1 1 1 1 1 1 


00 00 00 00 00 c 

I I I I I I I I I 


I I I I II I I I 


x o> 

CD — 

Jr ^ 

Ph co 


IOMN01OMWON X0©^hO^CIO 


+ 4- + + + + 


+++++ ++ 


tPhOO."ON(MCN 

++ ++++ I 


(O.XNt'O-H MH. 




++P+++++I +++++++++ 


S 2 £ 
* fc 3 
H a-w 


+++++++++ 


csC5GGdboot-~cioaow 

r—Ir-Hr—<r—CrHrHr—(rHr—( 

I I I I I I I I I 


i cvi csi csi 64 cm' c3 

I I I I I I I I I I I I I I I I I I 


Cq*-^^©CO©05 00 00 
coco©'^rfco^t , -t < © 
CMCS<M<MOIOI<MCN<N 

I I I I I I I I I 


H0«TP©0 


<NC©HON© OOOO ©rH©©© 


<000©»-<©©0 OlHNH©HOOO 


| | | | | I | I I | I I I I II I I I II I I I I I I I I I I I I I I I I I I I I I II I 


o 

o 

a 

a 


<D 

Ph 


n z W 
9 fecc 

fc-. Cj _ 
r* -4H ^ 

g ® 


©OCO©t^»CC<MOCO 

ONNtpNiH©cc© 

XXXOOHNNN 

•©©©0000001^-t^t'- 

"888888888 

©©©©©©©©© 


O rf < 

© CO 1 

© © ‘ 

§§888888 

©©©©©©©© 


O to CO O N CD CO 

-pohnhnocoo: 

© C O rH CM 03 CO © © 

§ C O X X X N I - l- 
rHwOOOCOO 
OOOOOOOO 


<N ©» t- CO © O CO t'r O 
© X X H H H x x X 
©©©coocoot-'-r-'-t-^ 

888888888 

©©©©©©©©© 


rfO©CO©t^OJCOCO 
© © O © N 10 X ■’p Tp 
GO OC CO '000000 

© © © go 00 00 i'-1'- 

888888888 

©©©©©©©©© 


IjSqo 

o u co 

g ® 


©OOOOOOOOt^OTf-TJi 
O H OJ 10 CD U rH (N Ol 
OhhcOMCOOOO 
^OOO 00 X 'A A ca. A 

*000000000 

©©©©©©©©© 


QQOcocOCOOi©© 
O' O O' A A A f- t - N 

0000 S 0000 

©©©©©©©©© 


CO Tp © c H < 

rH rH r 

OOOOOOOC-— 

OOOOOOOOO 

©©©©©©©©© 


g eo O CM O O O © 00 
CONhhCM©©© 

OOOOOOOoboOOOOO 

ooo§ 88§88 

©©©©©©©©© 


© rH H CM >0 © © -^ M 

NNNO©C3©<DcD 
© © © CM h - X X A 

© © © ce x 00 t'- r^- 

008008080 

©©©©©©©©© 


X <D 

s a 

Ph n 


©©©ccocoo<o< 


K5<CDX5<0<0<0< 


age 

® ® a 
H a*-* 


.’rrcooocooo’^'rrooo 

^t^O’-HTf'©©©©'^' 

0 corrrrrji-r^'HH-rriTr'rr' ©©©©©©©©.© K5 © © © i<5 © <0 <0 D 


O © 00 t>» t>00 O 


C3 

-*-H 

O 


JOOHON^NDN 


;<nnnnhnwhh 


O © CM 00 00 *H t'r CM NX©XNO'DNX ©XhXXOXI-'X O©CM©00tH00Q0O 

OJHNHHCMHCMH HHHHHHHHH HHCMHHNHHH Cl rH CM T—1 rH CM rH rH CM 


<D 

0 -. 

a os 

<D D- 

TJ Ih 

•rH 0> 

O +H 

d 

’o 

Q 


* 5.5 

HH H 


6 ©2® 

A o uQO 

O o © ^ 


-^^•^•^COCMCMCOCMCM 

^ © © © © © © »o © © 


<d ><5 »C Tp h o X X CM D1 
© © © rH fH © CM CM CM 
CM CM CM CO CO CO CC CO CO 


<DXtPXHtPXXM CO CO H CO rH CM CM O O tPCMhxh CMhhCM COCO CM rH CO CM CM rH 

©©©©©© ©" © © ©to©©©©©©© ©©©©©©©©© ©©©©©©©to© 


35 


O O 00 CM O 00 CO 05 
COCMOOOOCOrtH 


1 CO CO CO CO CO CO 


f^MOOO©NN 

©©©^HrHrHCMCMCM 
CMCMCMCOCOCOCOCO CO 


A i°® 
§ SZw 
p © 1 . 0 C 
O C QJ 


TPX<C< 

o © co c 

cc00l^t^O5C506cMCMCM 

’P'tTPC'.OOHHH 

CMCMCMCMCMCMCOCOCO 


CO 00 00 

TP rp-1« 
CM CM CM 


co CO CO 
CO CO CO CO CO co 


COOOtOXOOOCMO© OOOOHI^OCM^CM COCOCMOOOOOOCO 
CMCOt'»0©CM©©CO © O rH CM © CO CM rHCMCMCO©Tf<©Tj 1 Tt< 

t^*©©COI>rl^.ojci6o6 t0CDC0t^t^t^a50505 rHrHrH©lO©o6o6o6 


to to 00 t'- . - 

^ Th 05 05 © 


OO' 00 

VI' VI' Wrf WH wv Iw" ©<> ^0 

CM CM CM CM CM CO CO CO 


© co to t'-c 

TPrf HOOOCww 
CMCMCMCMCMCMCOCOCO 


»H © © © 00 00 00 

©©•OOOOrHr-*^ 

CM CM CM CO CO-CO CO CO CO 


c3 

n 


'I § 

PhD 


; u- ; ;oo ; .05 

.CM . .CM r .CM 

© • L • • | » • l _ 

rH©©0'-t--t''-00000005 

©CMCMCMCMCMCMCMCMCM 




T • -T • -T 

HCMCMCMCOCOCO^ 


00 


• T —1 

T • '7oo4. 

00 05 05 05 rH H rH i 


© 


CO 

^ CO CO 


00 


5 N N N 00 


CM CM 


3 


CM CM CM CO CO CO H*’ 
CM CM CM CM CM CM <M 


i; t t t t t 5 ; u ' b C tn u u *-.* C «-* u u, uJ n C 

aaaaaaftaa c.o.a,a&fiB,Ba a&aaaaaaa aaaaaaaaa 

HHH **1 *7 H < 1 H •*< < 1 H H <)•< << <) <i << <| «s) <d H •< •< <i <| «d <| ■< h <$ <) <. *7 


QfifififlflfiOfi fifififlfiPfiflP ppppppppp Ofififtfifippp PPPPPPPPP 


Tp Tf TP©©© <D<D<D T* © © © CO CD co ©©©©©© H<Tt<Tf©©©CO©© rf-H'^©©©©©© 

HHHHHHHHH HHHHHHHHH HHHHHHHHH HHHHHHHHH HHHHHHHHH 


rHCMC0^tO©r^00O5 rH OM CO ^ © CO t"» 00 05 rH CM CO 00 05 rHCMC0^©©l>00O5 rHCMC0^©COt^00O5 


TO 


> 

s 

x 

JZ 

O 

'd 

a 

C3 

a 

o 

+2 

03 

■H> 

TO 


C8 

03* 

6 

Sp 

<o • 

►—« l_ 

o 

o 

33 

4 § 

ra © 
> a 

tv . 

a" • 

of . 

-t — 

a a 

X tj 

h» c3 

§§ 

o 

o © 

PP © 

f® 

§?, 

£H 

a 

.O 

as 

05 

•tap 

W o 

Wp 

ho 

|p 

© -I 

rH M 

gp 

Si* 

rH C3 

S ^ 

'-O! 

od 

do 

►7 

od 

y A 

o< 

oH 

















































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


0,0 

w-H 


0 rH 

88 

O rH 

R8 

S 3 

OOO 

05 n 

050 

S-H 

05 O 

a-H 


<o ^ 

sg 

050 

S-H 


ON^OXCCOh 

-^COCOrfCOCO-rf^ 

OCCNO 
-1* ^ CO CO 
^ -*t« 'Tf* 

HNCOMNOJOCCOW 

OtOtCcOOtOcOt-CtC 

cocoeococococccoco 

to to ^ co os N 
00003®® 

CO CO CO to to to 

^f-H^HOOOStO^CDCO 
^•^'^CCCC'C’^CCCC 
N- N- I'- N- N- N- N* 

t-COiCCOOOONN 

CCN^hCCCCNCCNCC 

COOOOUOCOOOOGOGOOO 

CO’fCOONN’tCCW 

to to UC <Q t-C to to to lO 

00 00 GO GO 00 CO 00 GC OO 

GOtOrHGOr^CCCOCOrH 

lO ‘O to to to 'O to >0 »o 

OCGCCOCCCOOOOOGOGO 

05 05 05 05 05 05 05 05 
t>- t- r- t^- 

0505050505050505 

OOO 0 

1 ^ t> r- i'- 
0000 

OOOOOOOO 0 
r- 1 ^ i- t-~ t— 

OOO 000000 

ciooooio 

t>. i>. r>. t>. 

05 05 Oi 05 O 05 

050505050505050505 
NNNNNNNNN 
05 05 05 05 05 05 05 05 05 

N- t^» 1 ^. !>. t>» N- N- 

050>05J)05C301030> 

05050505050^0^05 
NNNNNNNN N 
050505050505050505 

0<35000>0>3i05© 

1 - tn. t - tr 1 -- l'- 1 ^ I - 

.5010092 
.5010100 
.5010107 
.5008346 
.5008351 
.5008352 
.500.8346 
.5008344 

.5008347 
.5007992 
. 5008007 
.5008008 

. 5010294 
.5010304 
. 5010308 
.5008542 
. 5008546 

. 5008554 

.5008182 

.5008207 

.5008220 

.5009670 

.5009670 

.5009673 

.5007948 

.5007940 

.5007958 

. 5009316 

. 5009322 

.5009323 

. 5007584 

.5007582 

. 5007566 

. 5007222 

. 5007241 

. 5007244 

. 5009082 

. 5009098 

.5009138 

.5007348 

.5007348 

.5007353 

. 5007001 

. 5007023 

. 5006998 

. 5009030 

. 5009034 

. 5009036 

. 5007284 

. 5007279 

. 5007280 

. 5006942 

.5006944 

.5006942 

. 5009024 

. 5009031 

. 5009040 

. 5007278 

. 5007281 

. 5007291 

.5006934 

.5006943 

.5006948 

. 5010094 
.5010096 
. 5010106 
. 5008348 
. 5008352 
.5008350 
.5008352 
.5008345 

.5008341 
. 5007994 
. 5008007 
.5008005 

.5010292 
.5010302 
.5010311 
.5008538 
.5008549 
. 5008554 
. 5008202 
. 5008198 
. 5008207 

.5009678 

.5009670 

.5009663 

.5007956 

.5007935 

.5007953 

.5009315 

.5009328 

.5009315 

.5007592 

.5007589 

.5007552 

. 5007222 

. 5007243 

. 5007241 

.5009075 

.5009091 

. 5009150 

.5007354 

.5007345 

.5007348 

. 5007000 

. 5007039 

. 5006981 

.5009034 

.5009035 

.5009030 

. 5007290 

. 5007280 

. 5007270 

. 5006948 

. 5006947 

. 5006932 

. 5009023 

. 5009032 

. 5009038 

. 5007279 

. 5007279 

. 5007290 

. 5006937 

.5006943 

. 5006943 

.5010089 
. 5010104 
. 5010108 
.5008343 
.5008350 
.5008355 
. 50081341 
.5008343 

. 5008.353 
.5007990 
.5008007 
. 5008010 

.5010297 
.5010305 
. 5010305 
.5008545 
.5008543 
.5008553 
.5008163 
.5008216 
.5008234 

.5009663 
.5009669 
.5009683 
.5007940 
.5007945 

.5007962 

.5009316 

. 5009317 

.5009331 

. 5007577 

. 5007576 

. 5007580 

. 5007222 

.5007239 

. 5007248 

. 5009089 

. 5009105 

. 5009125 

. 5007341 

. 5007352 

.5007358 

. 5007002 

. 5007007 

. 5007015 

. 5009026 

. 5009034 

.5009041 

. 5007277 

. 5007278 

. 5007289 

. 5006935 

. 5006942 

.5006953 

. 5009024 

. 5009030 

. 5009041 

.5007277 

. 5007283 

.5007292 ; 

.5006931 

.5006943 

. 5006952 I 

22222222 

1 1 1 1 1 1 1 1 

OOOO 

HHHH 

1 1 1 1 

coooooocc»cooooooo 

1 1 1 1 ! 1 1 1 1 

Tft T* Tf -«J 1 ^4 

HHHHHH 

1 1 1 1 1 I 

0)9)C)9i930>0)0)0) 

1 1 1 1 1 1 1 1 1 

eccccccccccccccccc 

1 1 1 II 1 1 1 1 

OOOOOOOOO 

rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

cccccccccccccccccc 

HHHHHHrHHH 

II 1 1 1 1 1 1 1 

IN<N<NNN<N<N<N 

NNNNNNNN 

++++++++ 

+ 212 
+236 
+236 
+ 236 

NNNCOOXXM 

,Hrd r -.ClM(N't'rtlrt 

cccccccccccccceccc 

4- + + + + + + + + 

H F-t rH lO 1-0 »0 

CC CC CC CC CC CC 

+385 

+385 

+385 

+356 

+356 

+356 

+381 

+381 

+381 

(MNNNNN’fi^'f 
<D<O<ONNNNNN 
N N N N N N N N N 

NNNOCOOOOO 

CCCCCOOCOCONNN 

cccccccceccccccccc 

+++++++++ 

COCOCOOOOOCO 

CCCCCCCCCCCCCCCCCC 

NNNOlOiOClO) 

OOOOOOOO 

77777777 

C? 05 OS 05 
OOOO 

7777 

t^t-t^oooooo 

1.11 1 1 1 1 1 1 

0 0 0 co 00 00 

to O O N N N 

1 1 1 1 1 1 

OOJOtOCOCOOOO 

tCtOtO'^t«'* ; t*' , t , '''1 , '*T , ''34 

1 1 1 1 1 1 1 1 1 

N N !>■ N N N O tO <Q 

1 1 1 1 1 1 1 1 1 

CC CC CO lO 1.0 tO rH rH rH 

CO O O CO CC CC CO CO CO 

1 1 1 1 1 1 1 1 1 

HHHOOOOOONNN 
OOONNN03 05 0) 
rH rH rH rH rH rH 

II 1 1 1 1 1 1 1 

t^^NNt^t^^r-< 

+ + + 4- + + + + 

CO iO f* N 

+ -M- + 

IOCCHN 00 N 00 NN 

4-4- 1 4-4-4-4-4-4- 

05 CO tO CC 05 00 

ONO-^Wr-IHOON 

OOtC^t>-tCCCCOtOCC 

i i 1 1 

tOCCnNCOCq^HCC 

1 1 1 1 1 1 1 1 

N-tOrfNNtOCCl'-rf 

+ + + + + + + + 4- 





OlNUGUJXOiOO 

OlOOOOOOO 

NCONNNNNCO 

1 1 1 1 1 1 1 I 

QXNh 

CC CO CC CC 

1 1 1 1 

OXiCC^XHiC-rti 

l^OCONNNOOOOO) 

rccccccccccccccccc 
! 1 1 1 1 1 1 1 1 

1 < 5 CO<ON<OO 
CC N O O O 05 
^ Tf Tt< ^ ^ CC 

1 1 1 1 1 1 

NNCCOOCNNNOO 
iOCCNhhOOOIX 
CC CC CC CC CC CO CC N N 

1 1 1 1 1 1 1 1 1 

CCOOtCNOOtOH 

NNNNNCC^^tO 

r-H rH i-H rH rH r-H rH t-H rH 

1 1 1 1 1 1 1 1 1 

CCtOCCNCCOCOtOtO 

XNNNNCCOCOCO 

NNNNNNNNN 

1 1 1 1 1 1 1 1 1 

^CCNtCCCOlN-^M 
05 GO CO CO *C tO »C <0 

NNNNNNNNN 

1 1 1 1 1 II 1 1 

^ 22222^2 
t 1 1 1 1 1 1 1 

OOOO 

II 1 1 

HX'NOO^OSHN 

1 1 1 1 1 1 1 1 1 

Nhhhhh 

II 1 1 1 1 

O—< N —«©N0©0 

r —1 »—< 1 —■» »—< f—i rH rH r—( 

1 II l I 1. Ill 

hhOhhhOhO 

rH rH r-H rH rH rH rH rH rH 

1 1 1 1 II 1 1 1 

^rHrHOrHNOOO 

HHHHHHH rH 

1 1 1 1 1 1 II 1 

-hhNhhOC 505N 
rH r-H rH r-H rH rH r-H 

1 1 1 1 1 1 II 1 

.5010205 I 
.5010212 
.5010217 
.5008449 
. 5008451 
.5008444 
.5008452 
.5008452 

. 5008-146 
.5008080 
. 5008102 
.5008098 

.5010359 
.5010366 
.5010380 
.5008598 
. 5008613 
. 5008632 
.5008244 
. 5008252 
. 5008256 

.5009819 
. 5009801 
. 5009778 
.5008010 
. 5007981 
.5007994 

.5009306 
.5009293 
. 5009268 
.5007570 
. 5007566 
. 5007523 
. 5007151 
.5007170 
.5007160 

. 5008952 
. 5008968 
. 5009027 
.5007269 
. 5007264 
. 5007272 
. 5006881 
. 5006929 
. 5006878 

.500S996 
.5008991 
. 5008986 

. 5007209 

. 5007205 

.5007193 

. 5006862 

.5006860 

.5006844 

.500S89S 

.5008898 

.5008895 

.5007128 

.5007121 

.5007129 

.5006779 

. 5006778 

. 5006783 


-fTfcO»OOOC'3—* o —; oo 

CWNCM.-vON I - N rf 

O 'O »0 N N N N N r-f* -t ■'£ 

O O O 00 OG 00 00 00 00 00 GO 00 

0008S8S8 00S0 

tO 10 <0 <0 <0 *0 <0 »o to to »o »o 


0 05 05 in (N 00 O 



•O r-H 05 N- tt CC 
CO CO »0 05 05 O 
'H-H-rocO't 
OOOXCOOO 

000888 

tO iO 'O O <0 to 


rtOWNif? OhcON 
toNNtoto»ooocqo5 
l - C5 05 05 lO 10 10 

§ 05 05 1 - t- n- 

gggggggg 

iO iO >0 *C >C “5 '•G *0 ‘O 


o —• co co cc» ... 

CCCCCOiO‘OtONNC.. 
- - - } i'- 

“18888 
i O tO O to 


CO CO CC tO CC CC N N N 

§ 05 051'* r» i-- i'-i^> 

88888888 
10 lO 10 lO >0 »o lO *o 10 


<C co <o n —< r'- -h a: co 
CO CO CO 05 05 05 O O N 
•0 o o co o o co ro co 

05 05 05 F- l- I- 

000000000 
000000000 
10 0 >0 >0 O iO 1010 <o 



N H N N N t- C 

tocococotoococo 

N 05 ^ CC 
CO tO CO CO 

05 N f- N <fi CC O M OO 
t-O co CO to to <0 to CO LO 

<0 050N<0<0 

<o to CO co to to 

LG X O'- O CC "t O <0 N 

co to *o co <o CO to o *o 

t0XOC0 05r<<0 05rt 
to to CO to tO o »o to co 

05HMNHNOCOH 

<C<00<00<0<0<0<0 

N 05 O W N 05 rH t- O 

>o to o o *o <o co <o o 

CCOCCKIOCCON 

rHN00r-4C50r-H 

N N N N N rH N N 
NNNNNNNN 

22.17 
22.36 
22.44 
22.42 

t£C5NNNNC5C5CO 

00NNX05COHH 

25.38 

25.09 

24.69 

24.72 

24.66 

24.52 

NfNC5tNOC5N 

iOOt>»tOiOCCNOOO 

CCCCNNNNNNr-i 

NNNNNNNNN 

'fSNCSCOOtONO 
05 00 00 05 O H CO rj< CO 

r^l^t^t^QOOOOOOOGO 

rH r-H r-H rH r-H rH rH rH rH 

tOCONONNONN 

t--.»otOtOtO^^CCCC 

NNNNNNNNN 

HiOOWNNCCtOW 

OMOMNhhOO 

N r-H r-H rH r-H r-H rH rH rH 

NNNNNNNNN 

OXhN05H<C:1' 

rH I- CC GO 

OCONI^OOOOOOON 

N 05 rH 050 O 

XOMOMCCNHH 

OOOO5O5O05O5O5 

05050000N05000 

OOMXOONtCX) 

hhNhhNhh 

N rH rH —1 

NrnNr-HrHNrHrHN 

N ri N rH N N 

rH<NNNrHNrH<NN 

NNNrHrHNr-HrHrH 

hhWhININhhIN 

NNNr-HNNrHrHN 

CCCCrHCCrHCCO-N 

rHHJCW 

tJ<h(NhNNC5NW 

■’J'CCNN^CC 

^tJt^NNCCNHH 

^NO^NNHCOrt 

CCNNNCCCChhh 

CCN^tONrHrHCCO 

to id »6 »o t6 »o *6 to 

to to to o 

tOtO <0 to tO tO rf uC tO 

to to to to to to 

LOtOiOtOtOtOtOtOtO 

<o <o vi to vi to »c <o <o 

t0<0>0<rf<0»0«j»0i0 

i0i0<0<0t0<0<0<0<0 


tO 10 to C 

eS n c 


5 CO CO CO 
5 05 05 05 
I N N N 


8888 

N CO CC CO 


)COCONt>HN^( 

HHHHOC 

Tt< Tf Tf< 05 05 05 
N N N N N N 


•O 10 co (M CO co 

10 IC 10 H H H 
N N N CO CO CO 


• 05 GOO N CO 
05 05 © O © 05 © 05 05 

cocot^cococoio'-f’-r 

NNNCOCOCOCOCOCO 


05C5r^Tf^TpcoF 
N 1^ 4 -T ^ O CO ^ 
<N<MCNCOCOCOCO<COCO 


33 


*<< ’f O Cl lO H CO C 


1 lO rH rH rH . 


.H 05 05 05 

GO GO CO iQ iO i-O CO cO CO 
<N<N<NCOCOCOCOCOCO 


iOOON*0‘OC 


S? 


N N N N N N N 


iO CO CO 

CO 05 05 05 

NC1NW 


NNN00 00t^©00t^ 
CO CO CO 1-- t'- 05 CO 00 

NNC^NNNNNN 


5 »0 <N CO 05 

> co co 06 00 

< ^ -f 05 05 05 
I N N N N N 


ONN^Tf'fOOO 

lOtCiOH-HHCONN 

<NN<NCOCOCOCOCOCO 


OO^NOOCO^fN^© 

NXNhiOOOCOO 

C5 GO C50 -h O O CO »0 
CO © <C CO CO CO a 3 ^ 
N N N CO CO CO CO CO CO 


t>-t^.»0t0<N05 05C0r-H 


N N N CO CO CO C 


nnncococo: 


Apr.28. 

Apr. 28-29... 

Apr. 29. 

Apr. 29. 

Apr. 29-30... 

Apr. 30. 

Apr. 30. 

Apr. 30, 
May 1. 

May 1. 

May 1 . 

May 1-2. 

May 2. 

May 5. 

May 5-6. 

May 6 . 

May 6 . 

May 6-7. 

May 7. 

May 7. 

May 7-8. 

May 8 . 

May 21. 

May 21-22... 

May 22. 

May 22. 

May 22-23... 
May 23. 

May 27. 

May 27-28... 

May 28. 

May 28. 

May 28-29... 

May 29. 

May 29. 

May 29-30... 
May 30. 

June 2. 

June 2-3. 

June 3. 

June 3. 

June 3-4. 

June 4. 

June 4. 

June 4-5. 

June 5. 

June S. 

June 8-9. 

June 9. 

June 9. 

June 9-10_ 

June 10. 

June 10. 

June 10-11... 
June 11. 

June 15. 

June 15-16... 

June 16. 

June 16. 

June 16-17... 

June 17. 

June 17. 

June 17-18... 
June 18.1 




Afloacia 


QQflQapfiOQ 

flflqqflfififlfl 

aaflofifiafifl 

^Tf<rflOtOtOlOlO 

■<<■<<! 'C ■< *’1 

tO CC CO CO 
*t*<*<*4j* 

r^Tji^tOtOtOcCcCCC 

•< <! ■< ■< ■< -C -< 

-'t* Tf <0 »0 LO 

'^Tji'^iOiOtOOOO 

<! <) <i <1 •< <! <1 < <1 

Tf<Tf<Tt1LOlO»OCOCOCO 
<1 <4 

Tj»^tirl<<OtOtOCOOcO 
<< <j << cj << <; <j <; 

Tt<T}<Tt1lOtOtOCDCOCO 

H M X *0 co N X 

05 O rH N 

HC^X'ttOONXOS 

r-H N CC Tf tO CO 

hNM^‘OON 00 05 

HNW^tOONXOl 

HNXK<OONX05 

HNX^ftOONX05 


JZ 2 b. 
S <X> 

> g 

So 

1-1 

Oj 

Sir.' 

0*6 

5C 


o - 
o © 
cs a 

as 

S»J 

y jg 


>» 

u 

8 * 

§° 

■Si -1 


2 jo 

^ bi 

o*C 

5C 


CO (- 

■3 ® 

a 2 

c3 a 

SO 

SU 

.0 
3 d - 
H 3 

05 

oH 

fc 


3d 

o 

ad 


a 


s.ga 

p,§ 

oMO 

£ 


o . 

5 © 

ii 

a 03 

3°. 

a. • 

wi 

.O 
o „ 

5 >> 
d« 
£ 


M 

aT 

3,- 

P g 
Sg 
0.0 

54 

do 

fc 
















































































































Pendulum observations and reductions —Continued. 


172 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


a 

os 


Cl 


00 © 
00 © 

C5 O 

&-H 


S58 

a> © 


© r4 

ss 
© © 
as “H 


O 

© © 
© o 

§2 
05 Tl 


!NOO>ON-*hOCO 

''COOCOOOOOOOOOOOOOt'- 

^QOOOOOOOOOOOOOOOOO 

^>.05 05 05 05 05 05 05 05 05 
r\ r- i- w :" 

05 05 05 05 05 05 05 05 © 


OlONCOIMOOMh 

OOOOOOOOOOOOCOOOGO 

050505050505050505 
t- t- p- 

05 05 05 05 05 05 05 05 05 


^CGOOrfCOOOOHOOCO 
O O ‘C O O O O iQ uj CO © © 

CX)OOOOCOCCC3COOGOOOGCCOGO 

05 05 C5 05 05 05 05 05 05 05 05 G5 
L- t- I- t- l- P- t- L- 
0505050505 05 050505050505 


P'.MMrHaoooP'-p-oo 

o »0 to © T "S' TT -r 
©©©©©©©©© 

OOOOOOQQ© 

cococooocooooocoa) 

05 05 05 05 05 05 05 05 05 


TJ 

0? 

Mean 

s. 

0.500S962 

.5008967 

.5008968 

.5007209 

.5007216 

.5007220 

.5006872 

. 5006874 

. 5006878 

. 5009055 

. 5009056 

.5009063 

. 5007304 

.5007306 

. 5007310 

. 5006976 

. 5006970 

. 5006973 

.5009016 

. 5009019 

. 5009024 

.5007261 l 

.5007263 

. 5007277 

.5006938 

.5006936 

.5006935 

.5006922 | 

.5006931 

.5006930 

.5008369 

.5008380 

.5008388 

.5006626 

.5006628 

.5006634 

.5006274 

. 5006277 

. 5006282 

. 5007255 

.5007268 

.5007268 

.5005517 

. 5005526 

.5005527 

.5005189 

.5005190 

. 5005188 

O 

05 

h 

5-h 

o 

05 

'd 

o 

’tn 

Chronom¬ 
eter No. 
1838 

s. 

0.5008966 

. 5008970 

.5008961 

. 5007210 

. 5007214 

.5007218 

. 5006875 

.5006874 

. 5006875 

. 5009054 

. 5009058 

.5009059 

. 5007304 

. 5007305 

. 5007308 

. 5006982 

. 5006968 

. 5006968 

.5009023 

.5009019 

. 5009014 

. 5007260 

. 5007264 

. 5007275 

. 5006942 

.5006934 

. 5005925 

.5006917 

.5006941 

.5006930 

.5008359 

. 5008384 

.5008390 

.5006628 

.5006631 

.5006629 

.5006277 

.5006279 

.5006276 

.5007262 

.5007265 

.5007262 

.5005515 

.5005527 

. 5005527 

.5005188 

.5005191 

.5005189 

05 

Ph 

Chronom¬ 
eter No. 
1828 

s. 

0.5008959 
. 5008964 
. 5008975 

. 5007208 

.5007218 

.5007223 

.5006868 

.5006875 

.5006882 

. 5009056 

. 5009055 

.5009067 

.5007304 

. 5007307 

.5007312 

.5006970 

. 5006972 

.5006978 

.5009008 

.5009019 

.5009034 

.5007262 

.5007262 

.5007279 

.5006935 

.5006939 

.5006945 

.5006927 

. 5006921 

. 5006929 

.5008379 

. 500S376 

.5008386 

.5006625 

.5006625 

.5006638 

.5006270 

.5006275 

.5006287 

.5007248 

.5007272 

.5007275 

. 5005519 

. 5005525 

. 5005527 

.5005190 

.5005189 

.50051S8 

/*\ 

0) 

3 

Flex¬ 

ure 

- 11 
- 11 
— 11 
- 11 
- 11 
- 11 
- 11 

- 11 

- 11 

©©©©©©©©© 

rlHHHHHHHH 

1 1 1 1 1 1 1 1 1 

MMMMMMMMMMMM 

rH H rH rH rH H H H rH H H rH 

1 1 1 1 1 1 1 1 1 1 1 1 

—H rH —H rH —H rH rH rH rH 
rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

©©©©©©Os©© 

1 1 1 II 1 1 1 1 

ft 

2 

E 

Rate 

Chro¬ 

nom¬ 

eter 

No. 

1838 

GOOOOO^^Tftrtirji^ 

rrrr-r<M<M<MMM<M 

©©©©©©©©© 

OS©Oi©©©^Hj<Tj< 

OO OOCG © © © © to 

©CO©©©©©©© 

MMMOOOOOOOOOOOOOOO 

•OtOiONNNCOCOCOOOOOCO 

©©©©©©©©©©©© 

++++++++++++ 

OOONNNNNN 
O © © © © © 
©©©©©©©©© 
+ + + + + + + + 4- 

HHHCOOOOOMMM 
N N n r- 1^ N 00 00 <» 

4-4-4- + + H--r + + 

9 

'O 

A 

4J 

Chro¬ 

nom¬ 

eter 

No. 

182S 

© © © Cl CUM © © © 
-Hr—irH(M<M<M<MM'M 
HHHHHHHrtrt 

1 1 1 1 1 1 1 1 1 

MMMCO©©©©© 

*—1-HrHOOOOO© 
rH rH rH rH rH rH rH rH rH 

1 II II 1 1 1 1 

©©©©©©©©©©©© 

MMM©©©MMMMMM 

rH rH rH rH rH rH rH rH r-H rH rH rH 

1 1 1 1 1 1 II 1 1 1 1 

© © © M M M rH rH rH 

© © © i- P- r- 

777 i i iiii 

-HrH-HGOOOCO-r-r-f 

MMMMMMMMM 

rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

a 

<35 

> 

C5 

CO 

Pres¬ 

sure 

© rH O © H © Ci O M 

O5tOMHCDM05'tN 

rHt'-Hji0O©M0OM©MCO© 

© CO H © H © It Hf M 

t^.©rHt^©©©©rH 

++I++ +++ 

CO 

p 

# o 

£ £ £ 

® fe 3 

H o.*^ 

<M05-P©0i-J<00©© 

^r©©©<M(M-H-H© 

©©©©©©©©© 

1 1 1 I 1 1 1 1 1 

©<33©qonnh<u:m 

MOOOOOhhh 

MMMMMMMMM 

1 1 1 1 1 1 II 1 

©GO©'**©©©©©©©© 

t'.©*ji'9<M©MCO©MMM 

MMMMMMMMMMMM 

1 II 1 1 1 1 1 1 1 1 1 

M©©©©©Pt©ihj< 

©I.O’J'Hi'H'H'rtirrrr 

©©©©©©©©CO 

1 1 1 1 1 1 1 1 1 

NOOOMOOCO’frr 

©©©rXMM©©© 

i i 1777777 

lx 

c 

O 

o 

Arc 

rHHrHHOi-HrHr—1 05 
—H rH rH © —H rH rH rH 

1 ! 1 1 II 1 1 1 

HM©HHHHOH 
rH —H rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

©rH-HrH©©©00-H©rH© 

1 1 1 1 1 1 1 1 II 1 1 

rH©MHHH©©© 
rH rH rH rH rH rH rH rH rH 

1 II 1 1 1 1 1 1 

COOhhhhhO 

HHHrtrHrtrHrtH 

1 1 1 1 1 1 1 1 1 

s 

4-S 

05 

05 


hrouora- 
>ter No. 

1838 


s. 

5008777 

5008782 

5008769 

5007036 

5007039 

5007037 

5006682 

5006682 

5006669 

5008903 

5008894 

5008901 

5007170 

5007175 

5007182 

5006857 

5006848 

5006843 

5008955 

5008941 

5008927 

5007149 

5007149 

5007161 

5006803 

5006797 

5006784 

5006777 

5006796 

50067S3 

5008217 

5008242 

5008242 

5006478 

5006488 

5006484 

5006131 

5006135 

5006132 

5006900 

5006906 

5006909 

5005162 

5005186 

5005195 

5004850 

5001858 

5004859 

a 


o ^ 


© 





P 

T3 

_o 

c 

0) 

* 

Chronom¬ 
eter N o. 
1828 

8. 

0.5009433 
.5009439 
.5009446 
.5007680 
.5007689 
.5007688 
.5007325 
.5007333 
.5007326 

.5009406 
. 5009392 
.5009410 
. 5007628 
.5007635 
.5007644 
. 5007305 
. 5007312 
.5007313 

.5009421 
. 5009422 
.5009428 
.5007651 
. 5007647 
.5007665 
.5007310 
.5007316 
.5007318 
.5007301 
. 5007290 
. 5007296 

.5008847 

.5008844 

.5008848 

.5007054 

.5007061 

.5007072 

.5006702 

.5006709 

.5006721 

.5007478 

.5007505 

.5007514 

.5005772 

.5005790 

. 5005801 

. 5005458 

.5005462 

.5005164 


Pres¬ 

sure 


rJ©*'H©©TT , M©05M 

g©©©©©©©©© 

g 

r}<C3HN00Cl©ON 

©©©©©©©©© 

©t—©©©M©MCOM©© 

©©©©©©©©©©©© 

© M Tt* © -f © Pr —H © 
©©©©©©©©© 

OrH©NrlTf-<05© 

©©©©©©©©© 


Eli? 

2 


.©o©to©-r©<Mf- 

^jHOOiOiOOl-©©H 

© o © r- © © © © © 

©OOlOJOOJrHrlO 

rH©t^©0©©t^0l>©t^ 
© rH OO CO © © © © T -T © 

© © M M © ~i‘ © © M 
T?" © H H H C) M M M 

rH CO ©aor^©t-©© 
©M©©GO©HMM 


© 05 P 

EH ft 4 ^ 


„ ©©IMCIMIMMM'M 
° M<M<M<M<MM<M<M<M 

O ©©d©©©©© 
MMrHrHrHrHMMM 

mmSmmSmSmSSS 

83?38S3?3888S3 

t- j'l r- go og oo co 

rH rH rH HHHH rH rH 


C3 

-*■* 

o 

H 


c 3 

P 


JhOOOOOOOOO) 


s M rH CM rH rH CM M CN H 


05NC0005H000 05 
rHIr—I 00 r-1 H oi oi H r-< 


rH©rH©CO© 00 ©M 00©00 

C'iHNrlHHHHC'ifHHH 


©OOM©©-Ht^COOO OOCOO©©rH©©r- 
M rH M rH rH cl rH r-H rH HHHOiriC'iHiHiH 


fl.s 


^^^^©MrH-^MrH -*TM©MMMM©M 
2 © © © © © © © © © ©©©©©©©©© 


HTJ.01NHHOHHOWH 

©©©©©©©©©©©© 


CO M ■«* 05 M CO CO CO M ©M©M©nt<M©© 
LO 1C lO »C 'O IO lO lO lO ©©©©©©©©© 


a> 

Orx 

a as 
<v t> 

353 

O 4-> 

a 

*o 

o 


6 © 

r o in® 

o as H 


CO'OOfNO'fO'fO 

co^^OGOor^co©*^ 

© © © tO iO to rr 'tf © 

ao oo ao © © © l- 

MMMCOCOCOCOCOCO 


rH © 00 00 -t« rH r-I-*© 
COOCOH05CCHIOOO 

rH «—J rH 05 00 GO © tQ IO 
cooooO'f’TTr'cococo 
MMMCOCOCOCOCOCO 


©©©©©©P-0G00©00© 

I'.OOOOiO'OTiicOCOOOOO 

MMMCOCOCOCOCOCOCOCOCO 


00 CO M © CO CO © M 
P-COOO'5T'CC©M©M 

•^COCOCOtOCOGOl^OO 

©OOOOOOOO©©© 

COCOCOCOCOCOT-T-rT 


C'lNCNTt'ClHiOiOtO 

OCOOCOOOOOiHfH^i 

cococO'^r'-^r-C'LOtOtO 


6 <i>5<» 
2 

u§ 


(NcONO^OOO'V'O 

•OCOHOCONN-aU'- 

eA © © to © to © i-i i-h 
COOO(MN(N'f'Ti< 
MMMCOCOCOCOCOCO 


0-^00©©-rr©©© 

COP'»rHM©©PrTji0O 

coodcCNricic^ci 

© © © M M M rfi rH rj. 
<M<M<MCOCOCOCOCOCO 


)®N'^OTJlOHClOT}'f 


© © O M M M -r -t •'T -r 
NNNCOCOMCOCOCOCOCOCO 


COCOCO'T^^rCOCOC'l 
00 00 00 © © © t>- t- Ir 
WNNCOCOCOCOCOCO 


-rcocococM^oooot- 

©COCO©©©©©© 

©©©'CTJi'TTf’T’^r 


o 

H-> 

aJ 

Q 


So 

ft 


p • d 
® 3 5 
3 


• <M • • © - 

• M • • M . • Cl 

i2—<z}j<M<M^©©23*r 

^M^MM^MM^M 

HDflJOJiDOOiDtDG 

PPPPPPPPP 

3p3pEp3p3 


. <M 


© • 
© • 

ppppppppp 

pppppp3pp 


© . 
Jsto 


MMC'CCOCO-C-C'^©©! 

’313'3'3'3’3’3’3'3'3’3’3 

©©©©©©©©©©©© 


© 

WNWWCO’T’CvtO 


^*5 ^*5 ^* 5 E O E»j> t >* 

P PP P P P P P P 
©©©©©©©©© 


© iA> © © 


00 ' 
citC tattoo 


betoSohOMbCbJOMibo 

333333333 


QQflQQPPQO flfiQOflflfififl pppppppppppp ppppppppp ppppppppp 


^^T}<©10©0©<0 rj<Tf<^©©©©©© rr-^rr ©©©©©©©©© ^Tfi>!j<©©©ocOcO ©©©©©© 


tc 

.So 

m 


Hd©^ ©©N00O5 HN©r?©©NCOO) HN«H©©N00O©H<M r-t M ©-^ © © t>. 00 05 H N « tjuO© N 00 P 


M 

3M 

5 § 

CO H 

S3 

2o 

CO 

<D • 

«5“ 
u- r 
^ >% 
dM 
5? 


05 

O § 

s 

oO 

-+J 

°d 

<N ^ 

n r 

^ 03 
6^ 


fl . 

o m 

lo 

Ro 

•» 

It#- 03 

6^ 


Jsh4 

05 • 

.’OO 

Q S cT 

.°0 

3’3rC 

B9? . 

tO ^ >5 >h 

•9«®e 

«ooqo 

> 


U1 05 

flS 

S 03 
05 rn 
T3 W 

(h * 

<<d 

rH 03 

dO 



















































































































INVESTIGATIONS OF GRAVITY AND ISOSTASY, 


173 


© Ti 


rt« © 

rH © 

oo © 
dd 

CO II 
03 Ti 


© r-i 

oo 8 
Os ii 


oo 

g-H 


ss 

05 Ti 


05 *H 

S58 

05 Ti 


Tr»00li0^‘'f*r01{0 

OOOOOOOOO 

rj’ rj» tJ’ rf rjt ryi 

d^iOtftO^CCONXCCitO 

*-H •—1 *—1 >—< T—1 r—• r—1 T—l r—l © rH 1 —I 

xxxxxxxxxxxx 

HdOXONOna 
hhh Oh ©h h 0 

CCOOOOOOOOCCOQCCCfj 

©OOtO(NN©iOCO‘0 

XM<MX<M<M<M<M<M 

1- l>-l- t - t- 

©©’^COtOt'-rJtiOXX'^r- 
HHHMClClTCIHdMH 
© iO *0 *0 ‘O © tO to © © © ‘O 

03 ©OX N*t TfNH 

X T X X CO TT , *T Tf* 

© © © © © © © © © 

OOOOOOOOO 

X X X: X X X X x 00 
05 05 05 05 05 05 05 05 05 

ooooooooooo© 

X X X X x s r f S X X X 
©©©©©©©©©©©© 

©©©do©©©© 

xxxxxxxxx 

©©©©©©©©© 

ddodddddd 

X X X X X X X X X 
©©©©©©©©© 

dddddddddddd 

xxxxxxxxxxxx 

©©05©03©05©01©G3© 

ddodddddd 

X X Xj X X 00 XXX 
0303030303 03030303 

] .5007646 
.5007642 
| .5007652 
.5005890 
.5005892 
.5005894 
.5005554 
.5005561 
[ .5005558 

| .5006605 
.5006600 

I .5006598 
.5004845 
.5004844 
.5004848 
. 5004850 
. 5004843 
.5004852 
.5004524 
.5004512 

.5004506 

. 5006606 

. 5006604 

. 5006610 

.5004862 

. 5004856 

. 5004866 

.5004504 

. 5004516 

. 5004522 

. 5006814 

. 5006S20 

. 5006827 

. 5005055 

. 5005068 

. 5005073 

.5004736 

. 5004728 

. 5004736 

. 5007360 

.5007352 

.5007364 

.5007342 

.5007337 

. 5007331 

. 5005587 

. 50055S4 

. 5005604 

. 5005252 

. 5005248 

. 5005267 

. 5007302 

. 5007298 

.5007300 

. 5005552 

.5005554 

. 5005562 

. 5005198 

. 5005203 

. 5005206 

.5007647 
.5007641 
.5007649 
.5005893 
. 5005891 
. 5005887 
. 5005559 
. 5005561 
. 5005553 

. 5006604 
.5006600 
. 5006595 
.5004843 
.5004837 
.5004843 
. 5004857 
. 5004845 
. 5004856 
.5004536 | 
. 5004506 
. 5004498 

.5006617 

. 5006605 

.5006597 

.5004862 

.5004856 

.5004866 

.5004507 

.5004516 

.5004517 

.5006814 

. 5006823 

. 5006824 

. 5005064 

. 5005064 

. 5005067 

. 5004732 

. 5004729 

. 5004743 

.5007381 

. 5007358 

. 5007372 

. 5007347 

.5007311 

. 5007306 

. 5005586 

. 5005572 

.5005611 

. 5005264 

. 5005236 

. 5005264 

. 5007305 

.5007294 

.5007300 

.5005563 

. 5005549 

. 5005554 

.5005192 

. 5005199 

.5005216 

.5007646 
. 5007643 
. 6007654 
. 5005886 
. 5005894 
. 5005901 
.5005550 
. 5005561 
. 5005562 

. 5006606 
. 5006599 
. 5006601 
. 5004847 
. 5004850 
. 5004854 
. 5004843 
. 5004841 
. 5004849 
.5004511 
.5004517 
.5004514 

.5006596 
.5006604 
.5006623 
.5004861 
. 5004856 

. 5004867 

. 5004501 

.5004517 

. 5004527 

. 5006815 

. 5006S18 

. 5006830 

. 5005046 

. 5005073 

. 5005079 

.5004740 

.5004726 

. 5004729 

.5007338 

.5007346 

.5007355 

.6007336 

.5007363 

.5007356 

.5005588 

. 5005595 

. 5005598 

. 5005240 

. 5005261 

. 5005270 

. 5007298 

.5007302 

.5007299 

. 5005542 

.5005559 

. 5005571 

. 5005204 

.5005207 

.5005196 

222S2222S 

1 I 1 1 1 1 1 1 1 

22S222222222 

1 1 1 ! 1 1 1 1 II 1 1 

<M<MCI<NCI<MC1CICI 

HHHHHr—IHHr—t 

1 1 1 1 1 1 1 1 1 

r-H r-H r-H 1 —1 r-H rH i-H rH r—i 

1 1 1 1 1 1 1 II 

rH rH r—i rH rH r—l rH rH rH 1 —< r—i rH 
rH rH rH rH rH rH rH r—i rH rH rH rH 

1 1 1 1 1 1 1 1 1 1 1 1 

1 ©©©©©©©©© 
HHHrtHHHHH 

1 1 1 1 1 1 1 1 1 

CO CO CO ©5 ©5 05 CO CO CO 

ooooaoHrtHCOcooo 

COCOCO^rr-'r^f'rr-n’ 

+++++++++ 

OtOiONCIINCICICIQOO 

++++++++++++ 

©©©■^^^t^t>-l^ 

©©©©©©XXX 

NNNCOCOCONNM 

+++++++++ 

MMM©©©^^^ 

XXXMMMXXX 

xxxxxxxxx 

©©©©©©©© 

Tf^'t^H^'/'COOOOOO 

MMMMMMMMMXXX 

+ + + + + + + + + + + 4- 

COMM 

xxx©OiC>r-t'-r'T 

©©©OOiC^OO© 
(NCKMNNClHrHH 
rH 1 —1 t-H •—1 rH rH r—i rH r—i 

1 1 1 1 1 1 1 1 1 

cocorcr^t'-r^r-r-^t'-oo© 

©©©XOOXXaOCOr-Hr-Hr-l 

1 1 1 1 1 1 1 1 1 777 

<M<M<M^-^^XXX 

1 —•»—ir—<©©©©©© 

777 1 1 1 77 7 

rH rH l-H © © © © © © 

©0 © t- to to >o 

777 1 1 1 1 1 1 

©©©©©©TfHtlTf©©© 

-^TjtTtlTfHjlT}-©©©©©© 

1 1 1 1 1 1 1 1 1 1 1 1 

©OlOiXXXXOOX 

©©©©©©XXX 

1 1 1 1 1 1 1 1 1 

OHHicoxacici 

XMONHTfCOMXNN 

XCOHt>.©©HCCCO 

OOH©©dOJHOM 

X©r^©*0*-<05TfrH©T}'0 -<ti-«r©©MTj*©rJirr 

rH rH 

++ 1 ++++++ 

++ +++ ++++I 

++1+ +++1 

+ + + + + + + + 4- 

+ +++++++++ 

+ + 4-4- 1 4-4-4- 

HcoxeoNOoxco 

X X t- 1- t- t- 1 ^-r-- 1- 

777777777 

©h35CChcDO©«WON 

TfLC'tiOiO't'^codcxo 

Cldddd(N<NdlNCIr-H 

1 1 1 1 1 1 1 1 1 1 1 1 

©©©(MX©!'-©© 

tC©©^XMrHMM 

1 1 1 1 1 1 1 1 1 

'■*xxr^x©N<xx 

XXNNNNMNN 

MMMMMMMMM 

1 1 1 II 1 1 1 1 

MXX‘OtOX©©©©cOO 
hWO©W<OOMO>NM^ 
rHrHMM—l*-»NM 

II 1 1 1 1 1 1 1 1 II 

**}« 03 t- 03 X X tH. 03 03 
MMMrHMMi-l©5© 

rH rH rH rH rH rH rH 

1 1 1 1 1 II 1 1 

222^22^2^ 

1111 1 1111 

2222°22P222P 

1 1 1 1 1 1 1 1 1 1 1 1 

Mhhhh©C1©0 

r—l r—l r—i r—i r-H r—i r—i r—i 

1 1 1 1 I 1 1 1 1 

HQOdHHHHO 
rH rH rH r—1 rH rH rH rH r-H 

1 1 1 1 1 1 1 1 1 

HHdCOOfOHCl'—IHHH 

1 1 1 1 1 1 1 1 1 1 1 1 

r-H OI HHOOOO 03 
rH HHHHHH 

1 1 1 1 1 1 1 1 1 

COiON3)OOOOC5C 
w w CO O to 10 C H — 

''t'r'ooc.'ococo 
r- c © to © © to 

©oooooooc: 
©©©©cooo© 
©©©©©©© »o »o 

. 500641.5 
. 5006415 
.5006411 
. 5004670 
. 5004665 
. 5004665 
. 5004675 
. 5004654 
. 5004656 
. £004391 
. 5004350 
. 5004323 

. 5006474 
. 5006476 
. 5006472 
. 5004616 
. .5004608 
.5004598 
. 5004250 
. 5004267 
. 5004275 

. 5006730 
. 5006744 
. 5000735 
. 5004979 
. 5004968 
. 5004971 
. 5004631 
.5004634 
. 5004650 

. 5007161 
.5007172 
. 5007195 
. 5007175 
. 5007215 
.5007251 
.5005510 
. 5005522 
. 5005538 
. 5005149 

. 5005173 

.5005222 

.5007363 

.5007355 

. 5007365 

.5005600 

.5005601 

.5005612 

.5005244 

.5005239 

.5005225 

.5007968 
. 5007971 
. 5007979 
.5006191 
. 5006210 
.5006220 
.5005842 
.5005862 
.5005862 

. 5006965 
. 5006962 
. 5006965 
. 5005203 
. 5005207 
. 5005205 
.5005190 
. 5005179 
. 5005178 
.5004836 
. 5004831 
. 5004809 

. 5006774 
. 5006796 
. 5006S19 
. 5005013 
. 5005006 
. 5004997 
. 5004639 
. 5004663 
.5004680 

. 5007164 
. 5007172 
.5007174 
. 5005309 
. 5005385 
. 5005391 
.5005032 
. 5005024 
. 5005029 

.5007410 
. 5007452 
. 5007470 
. 5007456 
. 5007559 
. 5007593 
. 5005865 
. 5005898 
. 5005878 
.5005494 
. 5005567 
. 5005597 

. 5007498 
. 5007505 

.5007506 

.5005741 

.5005773 

.5005791 

.5005419 

.5005410 

. 5005368 

X CO to 05 CO © to OI OI 
L* X) © «3 I!3 to «C © 

©i-’tNMO'^XHCDdO 

tc co c it «5 cc '<£uo © m © © 

10 H >0 © OC H Cl O © 
to©© to ©»o tO©© 

©XXXMtCXXi-H 
to © © .0 © to to »o © 

to X © X © X © O CO ‘O C OOTf^MOOeOCia 

©©©to©©©©©©©© ©©©©©©©©© 

cot^iooicor^tococo 

CO CO Cl H Cn H © H *H 

© to ».*5 © co ec co to co 

©CCOOMH-OMCOtX 

©Tf rfOCOMHCTOO 

Oi © to h x to © X X 
lOiOrf'^XNXXX 

XrH©rf<x©r^ i oto©xx tor^x©©©©t'-Tj« 
M©M©<N©l'-M©MXr'- © ©©XO©XX© 

© © © © © © © © © 

•—t r—i 1 —1 r—1 H »—l f—1 T-H »—( 

c-c-H^occcoidcr 

Cl Cl OI Cl C4 Cl (M Cl Cl h r- h 

© © © © td »o »o >d id 

r—l 1 —1 r—1 rH r—< rH r-H r-H r-H 

©©©odd©©© 

MMMMMMMMM 

tdiddddddddcidd xx"r'* xx c-c-© 

HHHHHHHMHHNN r-i r—i HHHHHrlH 


HOOOOHOO^OOOO 

csrHrHMAiNMrHrH 


OJODNWCOOCCHfNCOOirH 

M M <N M rH N rH <N M* rH r-i d 


N00005COW00 05 
M M M M A rH M rH rH 


HC5 03HHHH005 

oi r-4 r-i oi oi oi oi oi r-I 


©OSM©tO©C>M©©Oi.-H 

oir-ioir-irH*oi*-Ioioir-Jf-ioi 


ONHOOONOOCO 
oi i-i oi rH oi i-i oi r-i i-H 


•rrMXHrTrXXMM COOlTt«cO’^iOCOCC^01'-*CO CO ^ CO CO CO CO OI r-i O 'HCOiOT'CO^NrH XXX ©^XM”*MMMX VHCO^HCOOON 

uo LC 1C LO in V3 IC »C IO td © © © td © © © © id © © ididiClOi-CiOiOiOiO lO »C 'O lO ic 1C 10 lO irj I0i0*0>0ici0i0i0i0i«i0i0 ©©td©©©©©© 


ICIOIONOIWihO^ 

cocoeo-rTr-rt s '»t'-D'* 

cococo , »r'^r'n*^t''T''n' 


ccNcoio^NOOrj'c/:r t c 

iHOJ-fCOCCCOWOlOCCCNl-' 

S *©did©©©i-'ii''ioi©x 
05 05 co co co co co ?o © r>- 

XXX©©©©©©©©© 


Ti’rj-CO’*'COOlOCOtD 
hhhCOCNWM 
cococo -T r'7''^''^ | M’Tr 


05C5C50000iCOCOt^t^O 

XXX , 'J' -, f'T<''tf'''*' - 'r©©© 


COOOQCOOONCO 

OCqOOt^MCOOH 

hhhNMWQQOO 

r- NOCSO^Tf co 

COXX©©© © © © 


uo O 05 05 05 OJ OI OI 05 05 OI 0-^0 X X O M O 


05ONC0O10TJIC0H10C0C5 

•** ^ ■<* © to to do x 

COCOCOCOCOCO'^'^'^rfTt'Tti 


0005 500IONN05 
cocOcoT'^tt'^t}'^ 


05001^-0505005 to 
OOOOiOJOCOCOCO 

CC CO CO V ^ to o lO o 


r^coioio*-Io5coTrto»oo5t^ 
XXXXXMMMM©Tt*rji 
-5 CO CO ^ V r}< ^ ’ • 


C5 aovcDCOMNO 

X©©Cl©MX©M 


05 O X o ^ N X 

1<T}ir}<OCCOO)05 0 ..- - 

co co co -*r ,, t 1 ^ ^ co co co co co co^ tj» 


U 

^ * ; © 1 

! rH 

. 1. 

iyi 

• _ • _l • 

^ ! 

jj j 

i j 

© 1 

; i i 

II!!!! 

•r-i • • M • * X • *Tt< • 

• —1 • • rH • • rH • ‘r-H • 

• X • • 03 • • © • 

* rH 

' rH ’ rH 

* 1 • 1 1 

M 
© rX 

:7 : 

. M . 

►J kL nr? 

CO . 

• x • 

_• I • 

• Tf< • • © • 

‘ A _L .r! 

OOHHHNM^MMMii< 

• 1 • • 1 • • 1 • 
t'Ht^.XXX©©©© 


I OI CO CO CO -r ^ T *-T> QOrHrHrHMMMXXXTji 
<T—»^r—«r—«r—ir—I t—<»—• C'lcSoiOIOIOIOIOIOIOIOIOI 


ticxbjbtuotxitxitcitxtfl 

333333333 

<<<<<<<<< 


U)tXltfjUtJjtLti:tCt£tCtCibC 

ppppppppppp? 


OI OI OI OI OI Pi Si OI CO 
bi t£ b£ t£ b£ b£) b£ tJj ti) 
ppppppppp 
<<<<<<1<<< 


OI OI CO CO CO ril © hhhhhhhhhhhh 


C-P.P-O.P-P<QtP«P« 

©©©©©©©©© 

mxjimmuiuiuiuim 


4JP+J+5+J+54J+J-P-P-P+J 

—.P*P-PiPiPiP<Q«CmP.Pit1, 
©©©©©©©©©©©© 
wwvimaiviviviviwwui 


04 Q 4 Q-P 4 Q 4 Q 404 Q 4 P 4 

©©©©©©©©© 

vimmwmviwmui 


fififiQOGOOA 

RflOfiflfiOfifififiO 

PQQOPQQQP 

OflOflOfififiO 

pQQQRQOQOflQQ 

fiflQfiflfiflfifi 

H 1 H H 1 © © >0 O © © 

TfT^Hf©©©©©©©©© 

TfTjlHj*©lO©©©© 

Tf»TjlTt< ©©©©©© 

•X^rt<TjlTtlT}«T^©©©©©© 

^^H^©©©©©© 

rHMX^^Ot-X© 

HNM^iO®NOOO)OHN 

HNMfiOtCMiOO} 

HMMtMONOOO 

fhMX^©©I^X©©«-hM 

r—i rH rH 

»-lMW^©©t^X© 


M 

a 

Q 

CO . 

II 

CO CO 

PO 

^0 »-4 

o^-> 


fc Jr 
© 

-p 

Jr *- 

£ 05 

Hi 

.0 

S 

oP 


© 
~p 
t>. »- 
,Q co 

&o 

0-4 

g d . 

03 

©P 


p 

o 

a 


co f- 

or 1 

o E 

ic 

CM . 

2h) 

do 

£ 


jfl M 
is 03 

00 34 
00 CO 

^p . 

k . t- 
0<i p 

f I 


*s 

U S 

21 O 

® . 

*5 

CO i 
05 

^ o 
oS 

5?; 






























































































174 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


'O 

o 


a 

cl 

& 


R 

Cl 


o o 

00 -11 

© Ml 


■*T rH 

© 3 

03 © 

© “H 


3! 


o © 

CO 11 
03 M 


©CrHCMGOOOCMX© 

^■Ori^HOOHr-^ 


© P» © © X 

r—I rH rH t—H rH 

03 03 03 03 03 


«CM«tN - 

CO 00 t - C 

© © © © 


' CO GO GC C /0 GO QO CC l - 


>.© OOOCOOO© 

s 00 a CO CO CO GO CO 00 00 
i © © © © ©o^©©© 


© © © 0> Oi 
t— t> p- 
© © © © © 


© © © © 
p- i>- p- p. 
© © © © 


coocoooooooo 

COOOCOOOCO'OOCOCOCCCOOOCO 

©©©©©©©©<©©©© 


©©©©©©©ooooo 

CO CO X X X X X X' X X X X 

©©©©©©©©©©©© 


c 3 

<L 

t-H 

<1 


rJ'CMOGCMXX'OCM© 
WMNNKC/’.KKCO 
© © © X X X © © 

• I— I'— I © >C © 1-0 © ‘O 
ecOOOOCCCO© 
ccoccocco 
lO © *0 © *0 *0 © *0 *0 


CM © rH © 
© © © ^ 

X C© © rH rH 

X O XI-I- 

ooooo 
ooooo 
© © © © © 


OXOO ©OOCMCM©CCCM'*fCMP-r-<CM 
nr © © rH wHNHOOiO'fl'flOWn 
r-*X'XX CJlNC'DNWW^’r'J'-HHrH 
i_- -d -c / ■ x o y x x o o o -o o o 

© © © © © © © © © © © © © © 


©(MO>OOn*©O^XXX 

HTr^O^HNCOtMNINlN 

(M (N OJ (N rr-r rH M- 

X X X X X- X O O CC o o CO 

888880808088 

10 O *0 10 *0 »o *o *0 *0 »o *0 © 


SoL 

a^n 

g® 


-tCDHN 
XXCMOOCOP-XXX 
CO CO O X x x © © *0 
• I - I'* !<• iO iO lO 10 lO 10 
«o©OOQOOOOO 
O OOOOCOOO 
lO'CiC^iOOiOiOiO 


O X X © CO 
© © O CO Tt* 
COOQ©hh 

o o 00 o 
© © *0 © © 


HCCNM C". HT<CM-f-t<©(©rHCMC 
'•TOO—1 XCMCM©©©©© © C 
*—■ X X X CM CM CM CM *h — 

P* C© CO CO xcoxxxocc 

8888 ggggggs 

lOiOlOO ICIOIOIOIC^'OIOICICIOIO 


COOOt^COCWOONWNN 

NMWOhhhNNMNN 

CMCMCMCMCMCM"Hrt’'r T irHrHrH 

XXXXXXCOCOCOCOCOCO 

888888888888 

© lO LO © to © © © © © © o 


a o -f. 

O fc GO 

^£rH 

g * 


rHOXCML'GCM'TXrH 

XXXCOCOOXX'^ 

CCDcOCCKiOOiOiOm 

• 1 - r ~ p. © *0 *0 © © © 

C©OOOOOOOO 

000000000 

».*5 i.O iC lO iC <C >0 >0 *« 


lOHHCOlC 
© X —< T rri 
X 00 ©Hf-1 
C 0 00 03 NN 
O' O O O Q 
OOOOO 
O iG »OiC »C 



©HINNHHlClOlOl 
r^CNC'KNINOJ^t’r'-'^^ 
X X X X X X CO CO CO O CO CO 

_ §888888 

iO iG iG >G O iG»G »G »G >C >G 'O 


(NcG^NO’t'n'CUNHC'G 
rH -fiGOHHNMNNMW 

XXXXXXCOCOCOCOCOCO 

888888888888 

iGOiGiGiGiGiGiGiGiGOiiG 


a 

o 

Q 


CO 

£ 

.2 


£ 


Co 

rO 

o 


3 


Q* 

*3 

Jj 

o 

© 

03 

rg 

O 


a 

o 


o 

O 


03 

© 


a 

a 

T 3 

o 

<x> 

P* 


cs 

*3 

h> 

o 

H 


x © 
© •— 

E ~ 


© 

C 3 


£ g fe o« 

5£®*£ 


cmcmcmcmcmcmcmcmcm ooooo 0000 xxxxxxxxxxxx OOOOOOOOOOOO 

HHHHHHHHH rHHHHH HHHH HHHHHrlHHHHHH HHHHHHHHHHHH 

I 11 1 I 1 I 11 I I II 1 1 I 1 I ! 1 I 1 1 I I II I 11 I I II II II II I 1 


cm <n © © © to *© 10 

CO^Oh-M^OOWCO 

“I - H—1—I—I—I—I—I—+ + + + + 


C M CO CO 
CM <M (M 

+ + + + 


CM (N CM CM CM lO LO ‘O X CO CO 

+ + + + + + 


XXX©©©'^’«^r}i(MCM© 

WWMXXXOCDCO©©© 

CMNNHHHHHHMHri 


oAu 

^ P © CN 

,a o -f' - 

o a 1 




■jr. © 

© (-1 

ir 3 

Ph « 


B £ £ 

® ® 3 
H p,*^ 


:oo 


a o r 

§*» 

° JhOO 

© 


C l CM CM X X X 


OOO©©©*^* - 

>G»G»G 00 (»X , J'W 


I I I I l I I I I I I I I I I l I I I I I I I I I I I I I l 


I I I I I I I I I 


< CM >0 lO »C -rr 


+I+++++++ 


X © CM CM 10 »Gr-(C 4 »G © CO O CO t' IN © CO rf N O *G COOOiGN^NOOCOMiGNN 

i-H H 

+ + + + + + + + + H- + + + + + + + + 4- + +4- + + + I + + + + + 4- 


CN CM r-H 

4- + + + + + 


11+ I I I I I I I I I 


OOONCMNCOWOOiGW 

rHCi'f©NXM'CXrHCCX 

^Hr-<CM©C^CMCMCMCMCM 

II 1 I I 11 II 11 I 


NiGCO^aiGCOCO^COrHO 

CMO©cC»OiOXX©©Xt^ 

+ + + + 4- + + + + + 4--f 


r-H r-H O »—< , 'f H H H 1 


■< CM * 


©OOXl-lOXrH*-lrHO© 


I I I I I I I I I Mill I I I I I I I I I I I I I I I I I I I I I I I I I I I I 


X CO X O X o 
CONCO©OON 
»0 IQ 1 C X X TT 
. II - »o «o *0 ‘O 
^Ogggggg 

iG UO iG WO »G iG IG 


CC CO 

'T rr 

10 10 


INCOHNCO 
CO CO P- © O 
X X X O rH 

x x x r- 

ooooo 

ooooo 

UOiGiGiG kG 


CCONCO 
© P- t''» CO 
O I- 

1 - CO CO O 

S 088 

kGkCiG >G 


(©’fCOi . _ - _ 

-OkOXrHCMcOX»OOX‘ - 
» CM CM X X *C iO ‘O Cl Cl CM 

--G CO C- 


X X X X c 


5 CO CO CO CO CO 


G 1 NOOC 5 ©H^ONCOPP 
&OOHCPC 5 COOXCOCON 
X © © © © © rH Cl 1-H x X X 
P N P N N P O O O >0 *0 >0 
OOOOOOOOOOOO 
OOOOOOOOOOOO 
iGiGkOkOiGkG»GkGkG>G»GkG 


G °X 
5U^ O'? 
O L® 

Q « 


C/3 © 

© H 

Oh w 


«c 


)GOOtOMHH-t 
IW'fXCN©©© 
CO CC CO X © © kG 10 LO 
•PP PkG>GkG»GkGiG 
«cOCOOOOOQO 
OOOOOOOOO 
lOkGkGiGiGiGkGiGiG 


P- © © CM CO 
© O X CO CO 
rH rH (X X 
© © © I s — P- 
O C- 


_ J 808 

kGkG»GkGkG 


kGXkOCM MIOHNMMHOONCCNP 
kO CM CM rH (NCMXWOPNH'HIOO© 
XOOO W’l'VkO'OkOXOOXH'iO’f 
PPPP X X X X X X CO CO' CO CO CO' CO 

8888 §88888888888 

kGiGiGiG kGkG»GkOiG»G‘G»G‘G‘G>G‘G 


COMMXPO^OOP’tiGkG 

OiOPHCMtfOHNXOCM 

hhhCMNN1"HHOhh 

XXXXXXCOCOCOCOCOCO 

OOOOOOOOOOOO 

OOOOOOOOOOOO 

kG»G»GiG»GkG»G»G»GiGkGkG 


cfe P. 


es 
© © : 
H P- + 


03 

C 

s 


.M-HHOCOCOIGOH IGCOXXCO COXXX ^CO»OXO»OOP-OOOI^ ©©CMPOXLOCMtOOPCM 

^WUCCViGPCC© O © P-cO lOXN'fl' CMHMkGH<kG©NP(NCOkG O^PH-CCCCOlOPPOX 

. ^'rrrrrrtTfkouc^ plcocococo co co co co icnoogocohoooo cm cm cm x 06 co cm x cm cm cc co 

rHrHi—lr—IHHH hH rH rH »H r-H *—< HHHH rH rH H rH CM CM CM CM CM CM CM CM rHrHrHrHrHtHTHrHrHiHrHrH 

CM X rH o O O X © O X rH © o © ©©X© T)<CHHOCOC!HO©0 ^ 10 CO CM O X CM h © © H X 

£cMr-5cMCMCMCMrHrHCM fH CM r—i CM r—i HHHr-i CMrHCMCMCMCMCMrHCMCMrHCM rH r—i r—i CM CM rH CM CM r-i r—i CM r-i 

R 

^’^hXXNXGOM CM ^ tT X CM CM X X »C X CM X X X X CM X X X CMiGkGkGXCMkG'J^J'XHO 

C;. . .... . . 

SiGkGkGkGkGiG^kGiG »GkGkGkGiG »0»OiOiO LG kG kG >G >G »G kG kG iG »G iG kG LOkOkOkOLOkOLOkOkO»OkO>0 

R 

kG(NNkGOON!OH> O X X rr O OOXO XNXMOXOC CMfNN iGPCMOCMrtPHHfOCM h 

HO©tfikOX»OOOP O^XNX XXX© kCOXHXOkG^PXNW C0OCMCM00XPPC0QC003 

'ChOOh’hhPPP CM CM CM CM CM CM©©© PkCfONHOHOHCGHO t^cdc6rjicOX’*rX'^Oc6»0 

XXXXXXLGkOkO OOOQOQkGkG »0 CD CO CD OOOOOOXXXOOO hhhhhhOOOCMNN 

XXXH- CM CM CM X X XXXX X X X X X X X X X -T 1 •'T tT X X X X X X rr ^ rf 


a cs 


o 

O 


4 4 

aguoo 

a ®h 


4 4 °« 

°a2;« 

a § t,» 
C5 0 


°0XP-PiOXCMPPP 

CMCMCM©CMCM^rfHr 

XXXrr^'rr-^r^iTt' 


^H’l'O© OOcOP 
PPPH'X H'kGiGkG 
CM CM CM X X XXXX 


OPkOXCMCMPiOPP»G>0 
O© ©©©©cDcDcDXXX 
XCMCMCMCMD3XXXXXX 


XPOMiTf X©CO©*hOOO 
OOOOOOXXXrHrH© 
XXXXXXXXX'rrrrrj' 


:a 


c3 

Q 




o 

• T • .5 

© © o o A 
CM CM X X co 


HH+JHH-P-PHH-P 

©©©©©©©©© 

imnmmuimwmm 


-H -H H- -H -H 


H H rH CM »OkOcDcDcip-P-P-XOO 


MkGk^COXMH'^H'kG 


aa&P, Qvh nnno 
©©©©© ©©©© 
uimmmm OOGO 


OOOOOOOOOOOO OOOOOOOOOOOO 


'|§ 


a a a 
® a a 


flfiqflfififififi pfififlfl PPPP ppppqppppppq pppppppppppp 


rjk 10 kC kO CO © CO XT rj! tT iO kO UG © © © rfi rr ^ ^ © © © © © © ^ rf rj* Tf -sji © © © © © © 

<1 <J*<"<^*< *<■<<!*<*<-<*<*<<1 <5 *<< <j<1 <5<; 


W) 

.2 d 
ui 


HNXM , ©©NCO© HCMM^k© ©t^OO© HCMXM-©©POO©OHCM HCMX©hCM^©©P0CC3 


ro 

a 

cl 

a 

o 

-H 

ccS 

■H 

CO 


P t-r 
03 

Si 

© . 

rH 4-3 

a 

o 

o)3 


c 

>3 

£ 

^ u 

•o ® 

3 E 

HO 
>d • 

oO 

5? 


a C3 

1 . 

T3 • 
pqO 

00 >4 

2 « 


ow a 


u. 

2 E 
g a 

go 

o • 

(N O 

dp^ 









































































































980.340 


INVESTIGATION'S OF GRAVITY AND ISOSTASY. 


175 


S3 

05 n 


X rH 
28 
© o 
S-H 


o o 

GO II 
05 H 


28 

83 

05 Tl 


05 rH 

S8 


C-©Tt<©©©X© 

XXrjirrcOXXX 

COCOCOCOCOCOCOCO 


C0005MOOON05N 

cmcjScmcm§<n§cm 

ooooooooo 

XXXXXXXXX 
05 05 05 05 05 05 05 05 05 


O 00 ‘CNN»ON> 0 M' 

xxxxxxxxx 

NNNWWNeilNCS 


050505050505050505 


© © rH -rr CM »0 


»0 »Q *-h 00 O - 

- (N (N H (N » 


OOOOOOOOO 

GO 00 X CO CO X X 'X X 

05 05 05 05 05 05 05 05 05 


oooooooooooo 

XXXXXXXXXXXX 
05 05 05 05 05 05 05 05 05 05 05 05 


ooooooooo 

00 00 00 00 00 00 00 CO 00 

05 05 05 05 05 05 05 05 05 


COL'Jh.fH'^OSNrH 
t ' D- t ^ CO GO 00 t- GO 

ooooooooo 

oooooooo 
-.00 00 00 00 00 00 00 00 
©©©©©©<©©© 


8 


0©0©©QCM-+*rH 

OOOOCCCCQNM' 
I'N N 'X 5 3 1-0 »D »0 

Ho «o § »o *c to »o to 


^•O'ONO'ftONO 

COl’ , f00O5O3rtiLOrf 
HHHCCWCCCOO 
XXXCC©©©©© 
-^OOC 


I-. rH CM CM CO X X 

©©OXXX©©© 
00 '/. M C C C O 1C »0 


OOr-iCOQOM V NcOCO 
MW^tC'COCO>C ’}"0 
X X X X tO >0 CM CM CM 

00 oooo© GO © '-O' GO © 


'fl-'fO'OCONOOO^O’TOO 
NNNC0C0C0OM300005C5 
C5COCOOOOC4C)(N(NNfl 
* 'l X X GO CO GO CO O GO GO GO © 


CM©©©CM' ,| t , ©'-r'*tt 
OOJOONCO^OOO 
^rXX©©©XXX 


'T'TrrNNI-COCOCO 
X X 00 GO GO GO GO GO GO 

888888888 

iO iC *o *c *o © © >o o 


O I"* O N iO f' N I- X 
XXX©© 

c*. © © © >o to >o 

ooooooooo 


%hO'0 05(NNN05 
O'J'iOt^&OO'TiCn' 
i-H*—i*-«coeo’<TOOO 
XX0CCXC2C© 

§80880080 

»C »0 tO ‘O to to »0 *0 tO 


NONINN^OOOOOO 
OOOWMM05 0 05 
X X X CO CO GO to to o 
Igggoo.- 


oorcooooc 
iO Uj »o iO ‘O 10 >o »' 


OCOK5HHHONOO 
'I’W’TOXOn'n’C 
X X X tO © 'C CM CM CM 
CC X X CO CO CO CO CO CO 
OOOOOOOOO 
O '00 OOOOOQ 
m in in 10 in m m © 


Tf0®0«?P5QWN©«N 
XI • >C Tf n fc o I' 00 N 05 O 
COWWOOCCiNNNNNO 
X X X GO GO GO CO CO CO CO CO CO 

888888888888 
tO »0 >-0 © © © © © © O © 


M-©COM©NODOM 
aO05WMMOOO 
X GO X GO CO CO X X X 


©©©©©©©©© 


NC0OH05 05h**HN 
XXX-H--(OX05t- 
■n-Tr^rt^i^i-xxx 
X X X CO CO CO GO GO GO 

888888888 

10 © 10 © © © © © © 


» »». * — v.'^ » — s 

ihM^iOCCK. 

X X X O © © t- I- I- 

* - “ * 5 2 o >c 10 


WWvC-v.^ 
rH rH rH X X X < 
X 00 X CC CO CO c 


N N OC' H (N (N GO 00 C5 
OOOXXXC5C505 

x x x © cc © © © © 


lOOSHiOiCCOXO^ 

COX , rDXN©rf'|i 

XXX©©»OCMCM<N 

XXXCCCCCOCOCCCO 



M'ShOHHI 005G0*7"J'I0 
cot^xxxxr^r^xxoo 
X M c J CO go CO IN N (N (N (N 04 
XXXCOCOCOCOCOCOCOCOCO 

888888888888 
1 C iC »o 10 »C iO iO 10 10 o 


HC0O«3 05«05XU5 
HOiCONNOOOO 
'-TXXCOCOCOXXX 
X X X GO CO CO CO CO go 

888888888 
GO 10 >0 10 o »0 GO 10 © 


ONOOXCD^OO- 
XXX © rH rH X X X 
*r "H' !>- 1^ t - X X X 
XXX©©©©©© 

8SSS88888 

10 10 *0 »o »o 'O GO 10 X 



2222222S2 

1 1 1 1 1 1 1 1 1 

05 05 05 05 05 05 C5 05 05 

1 1 1 1 1 1 1 II 

1 1 1 1 1 1 1 1 1 

rH rH rH rH rH rH rH rH rH 
rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 

xxxxxxxxxxxx 

rH rH rH rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 1 1 1 

CMCMCMCMCMCMCMCMCM 

rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 II 

05 05 05 05 05 05 O- 05 05 

1 1 1 1 1 1 II 1 

•^jiTf^fOOOOOO 

TtiTfrftXXXCMCMCM 

+++++++++ 

•O >C tO O 05 05 r)"t 
CJCROXXXNNN 

H rH rH »—1 H H H rH rH 

+++++++++ 

XXXCCcCCCrr^-^ 

CMCMCMXXXXXX 

7+7++++++ 

CCCOCOCCCCCOCOCOCO 

888888222 

+++++++++ 

+178 

+178 

+ 178 

+200 

+200 

+200 

+200 

+200 

+200 

+203 

+205 

+ 205 

XXXCOCOCCCMCMCM 

222222'^ , ' rt '2 

'CtOtOMXXNNN 
0000X0505 05 050505 

rH rH rH rH rH rH rH rH rH 

00XXNNNOC5O 

to to to cc CO cc CO cc cc 

II 1 1 1 1 1 1 1 

NNN 05 05 05 O O O 

OOOOOOrHrHrH 

777777777 

tOtOtO'H.-'ftTf.CMCMCM 

XXX05C505XXX 

1 1 1 1 1 1 1 1 1 

O505O5tOtOt0rHrHrH 
X X !/) 05 05 05 t- fr N 

777777777 

NNNOOOQOOiOtOtO 
CM CM CM X CO X X X X X X X 

rH rH rH rH rH rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 1 1 1 

XXXNNNNNN 

XXX050505CMCMCM 

1 1 1 1 1 1777 

CDCCCCCCCCC©XXX 
hhh^NCMXMX 

+++++++++ 

Hrf'Tj’GOCOtOcON'n 

N^fC0HC0CM05Tf.H 

N^XHiOOXHtO 

HtNCOCO'l’XtOrf 

rH CM X 05 tO CM X CO ^ CC CM CM 

tO^-fi-HTtitOtfCMrH 

OCMcCXHHTfCMX 

+++++++++ 

+ + -M-+ 4-4-4- 1 

+ + 1 ++ +++ 

+++++++++ 

1 +++++++++++ 

+++1+++++ 

1+1+++++ 

OCM^XNlOOOHQ 

H005XNI'®©® 

+ + H-+ + + + 4- + 

OXNMXX’t-05 05 
XCMOCMX hCMOJO 
CM 05 CM CM Cl CM CM CM CM 

1 II 1 II 1 II 

HCMCD05rfCOHH- 

OCMCMXtOcCtO-fX 

HHHHHHHHH 

1 1 1 1 1 1 1 1 1 

0^©XC5tOODH 

tOXCDXHNCXtO 

XXXXXCMCMCMCM 

1 1 1 1 II 1 1 1 

Xhh005 05INNhCM^C 5 
XC5-rCMrH©rriOtOCOcCX 
»— rnCMXXXXXXXXX 

1 1 I l 1 1 1 1 1 1 1 1 

t>CMrH05©OtOCOX 

hCMONXOhOX 

777 1 1 1771 

•»r©XtoCMOXOtO 

ICCCNH"^IOONN 

hh^^hhhh^ 

1 1 1 1 1 1 1 1 1 

222 ^H^zJ 2^ sr5 

1 1 I 1 1 1 1 1 1 

XXXrHrHrHrHrHOO 

II 1 1 1 1 1 1 1 

HHHHHHHHH 
rH rH rH rH rH rH f-H rH rH 

1 I 1 1 1 I 1 1 1 

M05NhhhhC005 05h 
rH H rH rn rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 1 1 1 

CMhCMhh©005X 

rH rH rH rH rH rH rH 

1 1 1 1 II 1 1 1 

NOvXXhOhh 

rH rH rH rH rH rH rH 

1 1 1 1 1 1 1 1 1 


f'-XOCO-*X»OQX 
CO X 05 Tf CO GO - • - 
© >0 © X X X *0 © 
t--. r- 1 — to to © »o • r, g 


XXX'COCOCOCOCOO 

ooooooooo 
ooooooooo 
to to *o »0 to *0 to to to 


rr^tCCOCOCCU^N 
N0 T,O'T©NhhO 
OOrHXXXOOQ 
CC X X CD © © © CC © 

ooooooooo 
ooooooooo 
to 'C >2 to *0 to to to to 


CO 05 to 05 o X X to *— 

OShCIOhNiO© to 

VtnWNNCMMW 

XXXCOCOCOCCCCCO 

“•0000 - 


HW'fl'iOX’tXNNXNX 

NOrrNXOH^rto^tNG'j 

X'TnNt'N'r-r'T'T’t’n 

XXXCOCOCOCOCOCOCDCOCO 


OOOOOOOOO OOOOOOOOOOOO 

ooooooooo oooooooooooo 
»0 © to ©©©©©© © © to © © © to © to to to to 


(NO* __ 

■•XNOO)C(_ 

I X X cc to © X CM CM 
; X X cc O cc cc c- 

-888? 


OW'fXO'OSNlN 

SSSgSgSES 

N N N CC CC O GO to »0 

888888888 

© © © © © © © iQ to 


OJCOM'NXH'ifWCO 
cCXOXCCI^^r-r’T 
X O O O I- 

I — GC CC C O © I ' 


CCJK-iNhXK-h 
OXCCXtOXOOX) 
n ^ 1- t - N CO n X 
XXXCCCCCCCCCCCC 

OOOOOOOOO' 

to tO to >o to to tO >o *0 


OSTCWOCNO'i 
N C (N N OC C (N CO (N 
(N M X tO »C CM Cl (M 
XXXCCCCCOCOCCCO 
OOOOOOOOO 

8ggS8©g8S 


X X - 


.. J> X CM X 

XOOi-'-nCt^-t^cC 

XWOCNNDOOC 

888888888 

to >0 to to to to to to »o 


CC to rH to O Ol X X CC X rH 
OhNOO03C0NX05h05 
ONNCOO I- f- D- t- X 

xxxi-'-r^r-^co- 

ooooSSSsoooo 

tO to »0 tO tO to to ‘O tO to to to 


‘O to C5 to to O O to -f 

X CM X CM CM >0 cc to CO 
. _ . . CC CO to X X X to to *0 

CO CO CO CO XXXCOCOCCCOCOCO 

-S 888888888 

»o *0 to »o »o *o to to »o 


HCMXXC0 05XXX 
XcCto»OOtQC5C5X 
©OOCMCMCMXX X 
X X X cc CO CC to *0 to 
SSsfiSs Q oo 
ooooooooo 
to ‘O ‘O to to to to to to 


CMXXNNXNCO 

0 GO to tO tO GO GO GO 10 

t^QXCMXCMtOQ ‘O 
tO CC ‘O to to CO to cc CO 

©CNCCX'TOWX 
IO CO CC cc ‘O CO to CC 10 

C0HMX05CCOQ 

tOCCcCtOtOCCtO»OCC 

t0CMrHI0 05CMr'-C5rHXXX 
c 0 cccct 0 t 0 cct 0 * 0 c 0 tocccc 

C 5 © © to © C5 O CM X 
tO © © © © 10 © © © 

HMLO-HOONC5CO 

© © to © © © © 1 C © 

NNiOHNtNX'CN 

HiOI'OHCMXtOiO 

OGOtOM050iOI-Q 

H’T05«©NXri<0 

CMOOhNCCNNO 

rr050XCCX*OXCM 

cOCD-^CDCMI'tCMCC© 

WhNO©iDOXO 

©r^©rrCMX©05XT?-C5© 

XtOl^COCCXrHXXCOCC© 

OOHCHtC-rtX 

XG 5 -'rXO 5 rHf-t 0 C 5 

© 'T?' © © ^T 1 © X © l-» 
HNNfO»rNXNO 

CM CM CM CM X X XXX 

HHHHHHHHH 


t-t^OOXXOOXXX 

rH rH rH rH rH rH rH rH rH 

CM CM CM CM CM OI CM CM CM 

OOC5©CMCMCMXXXXXX 

rHrHCMCMCMCMCMCMCMc5CMCM 

222222^22 

■vr T . TrTJ :* 1 :^; C Q C - 5 c ^ 

05H050C5 05005X 

CM©0-H©C5 05©t^ 

CM X X 05 © O 05 05 CO 

CMOOHHC5HOC5 

«XCM050H©N05XXC5 

CMC3CIHCHHNO 

OX-fX©lO©©rH 

hNhhhhCMhh 

CM CMCMCMCMrHrH CM rH 

CMrHCMHCMCMrHrHH 

CMCMOlCMCMrHCMCMrH 

CM H CM rH CM CM CM rH rH H rH H 

CM rH CM CM CM CM CM rH rH 

CMrHCMrHr-HrHrHrHCM 

XX-^-^tOXtCXrH 

TrCMCMCMCM^H^-iCMrH 

tOCMrHXXXXXrH 

CM CM X X CM CM (N CM 

to rH TH x rH X CM CM rH © rH CM 

HlNrf XNHHC5H 

tOXtOX©©HrrX 

to to to +4 to uo »C to to 

to to to 16 ‘6 »6 to to »o 

to to ‘O to to to to to to 

to to »o to »b to to to »o 

to to to to »6 «o »o tO to to to ‘O 

to to »6 »o »o >6 to + to 

to «o to »o teS to to to to 


C5COCO'rfC'lTr-rfO^- 

X05C0XX>0XCMX 

OC5C5Xc6cCrHOO 
X CM CM CM CM CM to to to 

xxX'n'^r^'V't 1 ^ 


4 t.’ 


COtOCCOXXOX° 

O O O 05 X X rH © rH 
XXMXCOCO’fGf’f 


*T U3 O GT GN G- O GN 

Ht^.G5-<TXC5XC50 

OC5XrrXCMCOtOt^ 
H0005 0 05HHH 
XXXXXX'^'O'rr 


NC5DHOOOMMH 

rrXXXX^XX-r 
05 05 05 1^" I''" t”* 05 05 05 
CMCMCMXXXXXX 


UJ -T’ 




C3N005000XXXCCN 

O5C5O)©©N$XX00XX 

CMOICMXXXXXXXXX 


QOCCOaOCiONOOO 

O5O5O5I^»r^-l'-O5O505 

CMCMCMXXXXXX 


CONNOOh-OiON 
rHf—IrHrH^-IrHXXX 
X X co’j’'r w rt> 


OMNONXrj'MO 

XtOXCOXCMt^-Xl'* 

CM T-i o ^ CM CM to to to 
MMMhhhXXX 
XXCOK^'V’C^'G' 


CDOiO't’tM'trj'X 
05 O t>» C5 t" Oj to CO CM 

•rtdtCHOHHOM 
0 05QNNN050C5 
CM CM ! 


I X X X X X X 


NhhOOOCMhN 

oooxxt^ooo 

xxxxxx^r’T'^r 


HOOHHHHCM*f 

X X CC >0 tO tO N N D 
CMCMCMXXXXXX 


05MOCMMXOC5XXNM 
X X X X) to to CC CC O CO CC 
CMCMCMXXXXXXXXX 


C0H'tOC05H05i0 

NcC050'tXNCOO 


_3 05 05 CM CM CM 
XXX^XXTf'n’Tr 


cm' CM CM 


CM • < X • 

CM • .CM • 

T—I rH CM CM C^J X 
CM CM CM CM CM CM 


CM 

cdciNNiicrJooooc 

(M CM CM CM CM CM CM (M C 


+j+j+j+>-P-P-P 

ooooooooo 

OOOOOOOOO 




rH rH CM CM CM X 


: 





• CM ’ 

• x • 

• © • 

• © • . 

• • CM • 

• CM • 

• 1 • 

• CM • 

• • 

• CM • 

• CO 1 • • « • • 1 • • 

• | • • .* 1 • J • • • 


+J+J+J+J+5+JPPP 

ooooooooo 

OOOOOOOOO 


>>>.>>>>>>» 

ooooooooo 


>>>>>>>>■> 

ooooooooo 


>>>>>>>>>>>> 

oooooooooooo 


►>>>>>>•>*?>?> 

ooooooooo 


• to _ 
i • » 1 • • 1 . 

XXrj.'TT'rj.iOtOtOo 

666600600 

OOOOOOOOO 

QOQPfiflflfiP 


QPPPPPPPP RPPPRPPPP fiPOQQQQPO PPRRRRPPP PRRPPRPflPPPP PRPPPPPRP ppppppppfi 


^^,^4^1^1/^CCCOCC Tf tO *0 tO CC CO CO rTTf^rtOtOLOCCCOCC ’fHTf'uOtOiOCO'CCCOcOCC h tO tO »C O CD O 'trji-TnOtOtCCDcCCO 


HNX'f‘OONOOC3 HCMX^tOONOOO H CM CO Tf *0 ©> N 00 05 HNX^tOOt^COO HCM CO tOCDM»050 hN HCMX^tOONXC h CM CO Tf tO CD N CO 05 


^ ^ »0 tO »0 O CO CO 


«j te 

eo rt 
1 ° 



ss 

■Me 

AS 

fe 

09 

£ 

O 

T3 

s 

fl 03 

T* 2 

HH 

•S 

J£ O 

ao 

rT 6 

*© u 

03 . 

>P 

03 • 

PSP 

9 © 

®e 

H 0 

li 

.d 

.d 

c9 

.0 

p« 
,C5 

8 *-• 

■£ 

ip 

© . 
8P 

oZ 

6 * 

od 

od 



55 

55 


■Pi 

44 I 
1 
P? 


O 


<MO 

d - 
>6 
oS 


c« 

> 


V © 

SE 

[tj C3 

,C5 
P • 
M P 
60 































































































176 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40, 


<&* 

P 

OS 

© 


10 H 

o3 

§ 5 , 

O <1 


00 H 

S 8 

82 

O Tl 


©COCiH<NClCO*<rCO 

«CQ?O;(X )00 00 t ^00 00 C 0 

^ooooooooo 
5 >.Q oodooooo 

rv 00 00 00 00 CO C/D CO CO CO 

H o> ©> © cs os © © os © 


OHNMOOO(NC>Oi 

ooooooooo 


o 


p 

d 


GOCC^HCDC'JCOiNrji 
rj< -r ic rH -H N N 

rrrfi'rrt-'t^i^coeoco 
• 00 XjOOCOCOOO^CO 
?QC-Q©OOQOO 
OOOOOOOOO 
I0i0>0»0>0»0i0i0i0 


OQO'OC0©CNCC(NM ifl-rOOCDNON-Hin^^* 
0'T'tH05 0N®0 03 0100 M*i < t0500000) 

iO»O»C00r^00rj<TT''rT' CO CO W O tD C O) CC W CO M M 
OOOOOOOCDCOCDCOCO GOOOGO:©CDCOC©COCOCDOCO 

800088888 §88888888888 

i.O »-0 ‘O *0 ‘O O »0 iO ‘O lOiOiOiOiOiOiOiOiOiOiOiO 


:c© 


S o, 
2fe® 

O® 


5^00 

o mcc 

© ^ 


o 1 


WHOOJNhNhO 

iO-?rrHHHNNN 

— — h t- u- j- co co co 

•X»MOOtCC f OO 

^888888888 

•O ‘O >0 'O >o 10 »o 'O IO 


O3*OCC-t<»»ON00N 
•»7 <iO‘CC'Q©©00*0‘0 
10 10 l-: x n n ti rf -r 

oo oo oo co co co © co co 

888888888 

*0 IO IO 1-0 to «0 LO »o »o 


O O CO CO T i 
Tf CO CO CO CO ' 
00 CO CO CO 'O 


5 rt* P- 00 CO ^ ^ 
) O ® OJ H ffi 03 
5 CO <N <N CO M <N 

- > CO CO CO 


888888888888 

LO o lo o »o to »o »o 10 10 10 »o 


NCl'-WOC'lrfNQ 

'r'j'iOOHCONNN 

HH’H'r^P-t-COCOCO 

• COCOOOCOCOCOCOCOCO 

*§§8388888 

lo 10 »o »o »c 10 »o 1C 


O CO .*0 (N CO N C 1*0 N rr M (N 
OC"0!C3CO'T*r030H0300 

__ . . COCCCOCOCOOtNCOCOiMCOCO 

_00 CO CO CO CO CO C© 00 00 00 CO CO 0 CO CO CO CO o o 

888888888 8S88888SS888 

LO LO ‘O iO LO © IO »C LO iolOLOlo*OlOlOlOlOlOlO»0 


HOOO-OCOOCO 
['-r-TOO-^NOO 
iO‘O*O000000TrTrrr 
*0 00 - 


O 

p 

d 

• rH 
-♦-> 

d 

o 

O 


S 

o 

<L> 

•§ 

•© 

M. 

§ 

co 

g 

O 

•S 

d 


rO 

O 

I 

1 


a 

P. 

a 

o 

O) 

•d 

P 

© 


§ 


o 

O 


000000000000000000 


I I! I I I I I I 


03003003 0 0 03 03 OOOOOOOOOOOO 

HHHHHHHHHHHH 

I I I I I I I I I I I I I I I I I I I I I 


C3 

« 


1 a fe.oM 

o a 1 




OOC3HHH(NINd. 

rHHH(N(N(NlNN(N 

+ + + + -' 


■rt< rrf O © CC P— p— P-» 
0300)0)0303000 

fH hhhhhC'3C'^ 

+++++++++ 


Safe 6w 
ggsfc® 


oi © 
CD M 

m 3 
ft M 


+ + - 


1 N W N CO 00 CO » 

777777777777 


MOMBfONS 


I+I+I ++ 


TOlOOOO«D>OOOOt' 


OH'OiO^OOhNOONtJ' 
H rH 

+ + + I I I + I + + + 


a£ g 

£ fe 3 

Eh p,« 


I^OOCCH-OWOiHO 

OOMHOOCOM>- 

rriO>0>C>OH , *T , Tt"i' 


3 O CN CO H C 


++++- 


o 

3- 


H©HMHM00© 


I I I I I I I I I 


TfiHHHO'tOOH H03H03C3 03 CCCNh03 03 

rH H H rH rH iH rH rH rH rH H rH 

I I I I I I I I I I I I I I I I I I I I I 


p 

p 

*d 

O 


QD 


6 o 

§£eo 

o moo 

32 * 

Q 


hSCONO^hOO 

OlOtOHCOCOHOO 

r-r^r-ooot^coi- 

• N N N O CO © lO LO lO 

°°8SSSSSS8S 

»o »o *o lo »o »o »o »o © 


OCONNCl'^N 
COOOOH-COiOCO^M 
LOIOIOOOCOCOIOIOIO 
CO GO C/0 CO CO CC CC CD CO 

888888888 

I0»0u3‘0i0i0>0»0i0 


CO LO 10 W CO H CO U O » © 10 
©©©COCOCOOOhOOO 
00 00 00©©©©©©©©© 

888888888888 

10 10 10 to LOi IO © IO «5 O LO © 


S O — 
w 

O M QO 

o ® 


tO«M»OOOH'C^C^'^CO 
HWCOlMOOON©^ 
OO^XhhhOOCOOO 
• t~* N N w © © *0 iO «0 

‘“SSSSSSSSS 

LO »Q ‘O L-0 »o 10 10 »o 1.0 


©OOOH-HNlOOCO 
H N 10 W CO «0 
O3 00 CChhh(Z)CO00 
OOOOOOI^*t^.t^COcOCO 

888888888 

LO LO 10 *0 IO 10 LO *0 LO 


N00C003C0O©©>QOlQh 
CC O h©O3HO3COC0(NC5N 
N(NC0>O*O©NC0C0C0C0C0 

ooooco©©©©©©©©© 

088888888888 

lOiOiOHOiOiOUOiOiOLOLOLO 


Ji ® 

£ 1 

PM rn 


J’C'&jCOCOlOhOiON 
g CD LO CD *0 CO CO LO »0 O 


S 2 ® 
® © p 
EH Ph-*-* 


.H'hnr NNHSTf 
^Ho: *0 r-’o(N 00 n© 

0 cooioidcoeoeococo 


CO Cl CO 0 CO LO c 


0C30000H<N<N<M<M<N 


© 

53 


O 

H 


ci 

a 

s 


e ‘C0NH-HON00O03 

^MOHMMMrHMrH 


10C3HO^C0 03 000 h 00 CO CO 00 O LO 05 <N Oi 00 CO 

<MrH(N(MH<NrHH<N (N HHH HHHHlNHHH 


iOMOOCOM-fMHH 

ilOlOLOlOLdLOLOldLO 


N«CIKNNhON COhOtTOlOhhMIMhO 
iOlolOlOiOlOlOlOlO lO *0 *0 lO lO ^3“ lO lo lo LO *0 lO 


© 

Or-. 

P c3 

© t> 

12 fe 

o 2 
p 
o 
O 


6 

§ 

O P^tH 


)HNNiOU5H'00O)O3 

<N<N<NHHHCOCOCO 

cococo^t''T.rfTj’Trrr 


hh<M'OcOlOCOCO<M 
03030©©<000c0 00 
<N<N<MCOCOCOCOCOCO 


HCO^OOfH-CQCONOOCO 

iCONMOOH-WdCOCOH 

OHOLOiOTP-rrCOOHMco 

H H H O'- Cl O H H H H H H 
COCOCOCOCOCOH’Hir-'rjirrH' 


4 4 0® 
V H 


0<M<MHHOiOH*rf 
00 00 00 ‘O LO rr CO CO CO 
<N<N<NCOCOCOCOCOCO 


HHHHOCOMON^IOO 
OOOCOM^00500005 
COCOCOCOCOCOCOCOCOCOCOCO 


. <N 
, _ • H 

! I. 


CC3 

p 


. . CO 

<M <N (N CO CO CO * 


_ • 05 • * H • • I • 
CO *1 • • I O O O H 
H0OCOO)C3O3HHhh 


8 .... . ... 

oioocHHHN • f 

HH<NM<N<N<M<NM^rT 


fipflQfiQflpQ 


§§sgg§ss§ 


LO 


§§igss§i§||| 


8 § 

ft« 


fifiOOfififififi flfififlfififififi QQpOQOfiftOQfifi 


^ rf Tjno LO U 3 <0 ® © 


rTTj'H'LOLOLOCOcOCO 


Tf^^HLOLOLOCOCOCOCOCOcO 


bJO 

.9 O 

02 


HIMCOH-IOONCOO) 


H<NCO^»OCDr^OOOi hNCOtJ-lOONOODhNCO 


53 

l 


p 

as 

P 

O 

© 

02 


± M 

M o3 

«o 

tiS 

© . 

S • 

0 n 

.'do 

M ^ 

Is * 

ft 2 a,* 



O ® 

- e 

pi r 

a ^ 

&H 

O'er 
p flO 

CO ^ 

o5°l 

W) 03 t*>M 

.g«SS 

2 *4 


•i 1 &« 

0 © 

OrP P 

6S 

agio 




% 























































































































Chapter II.—DESCRIPTIONS OF STATIONS. 


There are given below the descriptions of the 219 stations in the United States with 
the years in which they were established. The description is designed to enable one to re¬ 
cover the place where the pendulums were swung. The numbering of the stations is the 
same as that used in other parts of this volume. 

No. 1, Key West, Fla. (1896).—Post office, southeast basement room. The case was mounted on the concrete 
floor. 

No. 2, West Palm Beach, Fla. (1909).—Zapf’s Opera House, room in basement under north part of building. The 
case was mounted on a concrete pier against a stone wall. 

No. 3, Punta Gorda, Fla. (1909).—Punta Gorda Hotel, in the space partly walled in under the main entrance. 
The case was mounted on a low pier of concrete and brick against a buttress of the wall. 

No. 4, Apalachicola, Fla. (1909).—Observatory pendulum room on Weather Bureau signal grounds near the center 
of the Florida Promenade Park between Fifth and Sixth Avenues and First and Second Streets, extended. The case 
was mounted on a low brick pier. 

No. 5, New Orleans, La. (1895).—City Hall, hallway in basement of building. The case was mounted on the slate 
floor. 

No. 6, Rayville, La. (1909).—Dr. J. H. Wilkins’s office, medicine room in southeast corner of small one-story brick 
building south of the Vicksburg, Shreveport & Pacific Railway tracks and three and one-half telegraph poles west of 
the crossing of the Vicksburg, Shreveport & Pacific and the St. Louis, Iron Mountain & Southern Railways. The case 
was mounted on bricks cemented together and to the concrete floor. 

No. 7, Galveston, Tex. (1895).—Ball High School, storeroom on the ground floor. The case was mounted on the 
concrete floor. 

No. 8, Point Isabel, Tex. (1909).—Constructed pendulum room 2.65 meters north and 0.67 meter west of the lon¬ 
gitude pier used by Assistant Smith in 1906 and about 110 meters north of the lighthouse. The case was mounted 
on a low concrete pier. 

No. 9, Laredo, Tex. (1895).—Commissary of Fort McIntosh, room in the basement. The case was mounted on a 
low brick pier build against the foundation wall. 

No. 10, Austin, Tex. (capitol) (1895).—Capitol Building, basement room southeast of the rotunda. The case was 
mounted on the concrete floor. 

No. 11, Austin, Tex. (university ) (1895).—University of Texas, main building, Aquarium room in basement. The 
case was mounted on the corner of a concrete wall. 

No. 12, McAlester, Okla. (1909).—High school just east of the Masonic Temple, northeast corner of the shower-bath 
room on the ground floor. The case was mounted on three 6-inch cube stone blocks, each cemented to the concrete 
floor. 

No. 13, Little Rock, Ark. (1896 and 1914).—Post office, north center basement room. The case was mounted on the 
concrete floor. 

No. 14, Columbia, Tenn. (1909).—Old dormitory of the high and public school, in southeast corner of basement near 
bathing tank. The case was mounted on three 6-inch concrete blocks, each cemented to the concrete floor. 

No. 15, Atlanta , Ga. (1896).—State Capitol, northwest basement room of the Washington Street wing. The case 
was mounted on the asphaltum floor. 

No. 16, McCormick, S. C. (1909).—McCormick oil mill of the Anderson Phosphate Co., four and one-half telegraph 
poles west of the Charleston & Western Carolina Railway depot, in the southeast corner of the furnace room at the 
south end of the building. The case was mounted on a low brick pier. 

No. 17, Charleston, S. C. (1896).—South Carolina Military Academy (citadel), storeroom in the southwest corner 
of the ground floor. The case was mounted on the brick floor. 

No. 18, Beaufort, N. C. (1909).—Masonic Hall on Turner Street, one block south of the courthouse; small room 
near the center of the north side of the basement. The case was mounted on a low concrete pier. 

No. 19, Charlottesville, Va. (1894).—University of Virginia, basement of biological laboratory. The case was 
mounted on a low brick pier. 

No. 20, Deer Park, Md. (1894).—East corner of swimming-pool building west of the Deer Park Hotel. The case 
was mounted on a low stone pier. 

No. 21, Washington, D. C. (1900).—Office of the United States Coast and Geodetic Survey, New Jersey Avenue 
and B Street SE., pendulum room in southwest corner of basement. The case was mounted on a massive brick pier. 

No. 22, Washington, D. C. (Smithsonian Institution ) (1891).—Northeast basement of the Smithsonian Institution. 
The case was mounted on a brick pier. 


59387°—17-12 


177 



178 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


No. 23, Baltimore, Md. (1893).—Johns Hopkins University, basement of the physical laboratory. The case was 
probably mounted on a brick or masonry pier. 

No. 24, Philadelphia, Pa. (1894).—University of Pennsylvania, small room in northwest corner of basement of 
College Hall. The case was mounted on the concrete floor. 

No. 25, Princeton, N. J. (1894).—College of New Jersey, basement of magnetic observatory or electrical building. 
The case was mounted on a tall brick pier. 

No. 26, Hoboken, N. J. (1891).—Basement of the Stevens Institute of Technology. The case was probably mounted 
on a brick or masonry pier. 

No. 27, New York, N. Y. (1899).—Columbia University, in a small room in the sub-basement near the center of 
the front of the Physics Building. The case was mounted on a brick pier. 

No. 28, Worcester, Mass. (1899).—Worcester Polytechnic Institute, in the southwest corner of the constant tem¬ 
perature room of the physical laboratory which is near the middle of the north side of the basement. The case was 
mounted on a stone pier. 

No. 29, Boston, Mass. (1894).—New addition to State house, vault in northeast part of basement. The case was 
mounted on the concrete floor. 

No. 30, Cambridge, Mass. (1894).—Harvard College Observatory, basement room north of equatorial foundation. 
The case was mounted on the heavy stone doorsill. 

No. 31, Calais, Me. (1895).—Basement of high-school building. The case was mounted on the concrete floor. 

No. 32, Ithaca, N. Y\ (1894).—Cornell University, in the metric room in the northeast part of the basement of 
Lincoln Hall. The case was mounted on a tall brick pier. 

No. 33, Cleveland, Ohio (1894).—Adelbert College, in balance room in the west corner of the basement. The case 
was mounted on a large brick pier with capstone. 

No. 34, Cincinnati, Ohio (1894).—Cincinnati Observatory on Mount Lookout, in the basement north of the foun¬ 
dation of the meridian circle. The case was mounted on a low brick pier built on the brick floor. 

No. 35, Terre Haute, Ind. (1894).—Hose Polytechnic Institute, in the west room of the basement of the main building. 
The case was mounted on a large brick pier with slate top. 

No. 36, Chicago, III. (1894).—University of Chicago, constant temperature room in the northeast part of the main 
floor of the Ityerson Physical Laboratory. The case was mounted on a massive brick pier with capstone. 

No. 37, Madison, Wis. (1906).—University of Wisconsin, in the basement of Science Hall. The case was mounted 
on a brick pier. 

No. 38, St. Louis, Mo. (1894).—Washington University, in the south basement room of the chemical laboratory, 
which is near the northwest corner of St. Charles and Seventeenth Streets. The case was mounted on a low pier built 
on the brick floor. 

No. 39, Kansas City, Mo. (1894).—Franklin School at the northeast corner of Washington Avenue and Fourteenth 
Street, in a small storeroom in the south part of the basement. The case was mounted on bricks cemented to the 
concrete floor. 

No 40, Ellsworth, Kans. (1894).—Ellsworth County courthouse, near the center of the basement. The case was 
mounted on a large stone doorsill. 

No. 41, Wallace, Kans. (1894).—Stone residence northwest of station belonging to the Union Pacific Railway, in 
the basement. The case was mounted on a stone doorsill. 

No. 42, Colorado Springs, Colo. (1894). —Colorado College, small room near northeast corner of basement of Hager- 
man Hall. The case was mounted on a low pier built on the concrete floor. 

No. 43, Pikes Peak, Colo. (1894). —Small storeroom at south end of stone building on the east side of the sum mi t, 
The case was mounted on large stones cemented to the concrete floor. 

No. 44, Denver, Colo. (1894).—University of Denver, in the basement of Chamberlin Observatory south of the 
equatorial foundation. The case was mounted on large stones cemented to the concrete floor. 

No. 45, Gunnison, Colo. (1894).—La Veta Hotel, small room beneath the sidewalk at the northeast corner. The 
case was mounted on a heavy stone doorsill. 

No. 46, Grand Junction, Colo. (1894).—Brunswick Hotel, on Main Street west of Fourth Street, in the cellar under 
the northeast corner. The case was mounted on a low brick pier. 

No. 47, Green River, Utah (1894).—Palmer House, in the east corner of the cellar under the south part of the build¬ 
ing. The case was mounted on a low brick pier built on the concrete floor. 

No. 48, Pleasant Valley Junction, Utah (1894).—Residence of T. Arrowsmith, about 65 meters north of the Rio 
Grande Western Railway station, in the west corner of the cellar. The case was mounted on a low brick pier. 

No. 49, Salt Lake City, Utah (1894).—Small astronomical observatory in the southeast corner of Temple Block. 
The case was mounted on a stone pier 1 meter high. 

No. 50, Grand Canyon, Wyo. (1894).—Canyon Hotel, in Yellowstone Park, in the unfinished basement at the west 
end of the main building. The case was mounted on a low brick pier. 

No. 51, Norris Geyser Basin, Wyo. (1894).—In Yellowstone Park, in a small room at the entrance to the storehouse 
west of the lunch station at Norris Geyser Basin. The case was mounted on three wooden posts driven into the ground 
and braced. 

No. 52, Lower Geyser Basin, Wyo. (1894).—Fountain Hotel, in Yellowstone Park, in an unfinished room in the 
basement at the north end of the central wing. The case was mounted on a low brick pier. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


179 


No. 53, Seattle, Wash. (university ) (1899).—Washington State University, just northeast of Lake Union, in the 
physical laboratory which is near the east end of the basement of the main building. The case was mounted on a 
masonry pier with marble top. 

No. 54, San Frandsco, Cal. (1891).—This station is probably located in the Davidson Observatory in Lafayette 
Park. The case was mounted on a brick pier. 

No. 55, Mount Hamilton, Cal. (1891).—Lick Observatory, on Mount Hamilton. The case was mounted on a 
brick pier. 

No. 56, Seattle Wash, (high school) (1891 and 1899).—High-school building, in a small room used for storing arms 
partitioned off from the northwest room of the basement. The case was mounted on the concrete floor. 

No. 57, Iron River, Mich. (1909 and 1910)—High school, just north of the center of town and two blocks west of the 
railway depot, in a small room in the basement, which is near the foot of the stairway leading from the western one of 
the main entrances to the basement floor. The case was mounted on three bricks cemnted to the concrete floor, one 
brick under each footplate. 

No. 58, Ely, Minn. (1909).—High school, 1905, small storage room under stair landing in west end of basement. 
The case was mounted on the concrete floor. 

No. 59, Pembina, N. Dak. (1909).—Public school, also used as high school, temporary room constructed in west 
corner of the basement. The case was mounted on low concrete pier. 

No. 60, Mitchell, S. Dak. (1909).—Dakota Wesleyan University, College Hall 1889, chemical storeroom in the south 
side of the basement about 30 feet from the southwest corner of the building. The case was mounted on the concrete 
floor. 

No. 61, Sweetwater, Tex. (1910). —Cyclone cellar of Russell Rhoades just to the rear of his dwelling, which is the 
second house on the east side of the street leading south from the Texas & Pacific Railway tracks to the Sweetwater 
Mineral Springs Park. The case was mounted on the concrete floor. 

No. 62, Kerrville, Tex. (1910).—Lowry Block, a little south of the courthouse grounds, in the basement. The case 
was mounted on the concrete floor. 

No. 63, El Paso, Tex. (1910).—El Paso High School, North Kansas and Arizona Streets, small room under stairway 
in the southwest side of the basement and near the outside basement door. The case was mounted on the concrete floor. 

No. 64, Nogales, Ariz. (1910).—Public-school building, small room used as library and storeroom in the south 
side of the basement. The case was mounted on a concrete pier. 

No. 65, Yuma, Ariz. (1910).—Public-school building, corner of Second Avenue and Third Street, a temporary 
r oom constructed in the southeast corner of the basement room which is to be used for manual training. The case was 
mounted on the concrete floor. 

No. 66, Com-pton, Cal. (1910).—High school, in the northeast corner of the southwest corner room of the basement. 
The case was mounted on the concrete floor. 

No. 67, Goldfield, Nev. (1910).—High school, corner of Ramsey and Euclid Streets, in small oil room on the boys’ 
side of the basement near the northwest side of the building. The case was mounted on the concrete floor. 

No. 68, Yavapai, Ariz. (1910).—Yavapai Point, in small tunnel on the rim of the Grand Canyon, 1.2 miles east of 
El Tovar Hotel. The case was mounted on three stones cemented to the rocky floor of the tunnel. 

No. 69, Grand Canyon, Ariz. (1910).—Bright Angel trail, in a tunnel on the mining claim of Mr. Cameron near the 
bottom of the Grand Canyon, 55 paces west from the steep part of the trail known as the “corkscrew” and 12 feet above 
the bed of a creek. The case was mounted on three stones embedded in a 4-inch layer of concrete on the rocky floor 
of the tunnel. 

No. 70, Gallup, N. Mex. (1910).—Public-school building, temporary room constructed in the northeast corner of 
the basement. The case was mounted on a low concrete pier. 

No. 71, Las Vegas, N. Mex. (1910).—Normal school on Main Street between Eighth and Ninth Streets, East Las 
Vegas, girls’ dormitory, a temporary room constructed in the southeast corner of the west room of the basement. The 
case was mounted on the concrete floor. 

No. 72, Shamrock, Tex. (1910).—Cyclone cellar near the northwest corner of the residence of E. H. Small, about 
one-half mile southwest of the main part of Shamrock. The case was mounted on the concrete floor. 

No. 73, Denison, Tex. (1910).—High school, northwest corner of Main Street and Barrell Avenue, in basement 
storeroom between the physical and chemical laboratories. The case was mounted on three concrete blocks, each 
cemented to the concrete floor. 

No. 74, Minneapolis, Minn. (1910).—University of Minnesota, constant temperature room, near the center of the 
basement of the physical laboratory. The case was mounted on a stone plinth 4 inches thick cemented to the tile floor. 

No. 75, Lead, S. Dak. (1910).—High-school building, vault near the middle of the east side of the basement. The 
case was mounted on three concrete blocks molded in place on the concrete floor. 

No. 76, Bisviarck, N. Dak. (1910).—Will School building, superheating room, center of basement. The case was 
mounted on a low concrete pier. 

No. 77, Hinsdale, Mont. (1910).—Public school, middle of the north side of the basement. The case was mounted 
on a low concrete pier. 

No. 78, Sandpoint, Idaho (1910).—Farmington Central School, alcove under the stairs of the main entrance in the 
middle of the north side of the basement. The case was mounted on three bricks, each cemented to the concrete floor. 


180 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


No. 79, Boise, Idaho (1910).—High-school building, new (1908) east wing of boys’ dressing room in south part of 
basement directly under the Tenth Street entrance. The case was mounted on three bricks, each cemented to the 
concrete floor. 

No. 80, Astoria, Oreg. (1910).—’Federal Building (customhouse and post office), temporary room constructed in 
the west part of the basement. The case was mounted on three bricks, each cemented to the concrete floor. 

No. 81, Sisson, Cal. (1910).—Sisson Tavern at Berryvale, about 1 mile west and £ mile south of the Sisson railroad 
station, a temporary room constructed in the basement under the southwest corner of the main part of the building 
The case was mounted on a concrete pier. 

No. 82, Rock Springs, Wyo. (1910).—City Hall, room near the middle of the southeast side of the basement and just 
east of the boiler room. The case was mounted on a low concrete pier. 

No. 83, Paxton, Nebr. (1910).—Globe Hotel, cellar under the storehouse at the rear of the hotel. The case was 
mounted on three bricks, each cemented to the concrete floor. 

No. 84, Washington, D. C. (Bureau of Standards), (1910).—Room No. 16, near the center of the basement of the 
physical laboratory or main building. The case was mounted with one brick under each footplate cemented to the 
concrete floor. 

No. 85, North Hero, Vt. (1909 and 1910).—Irving House, middle of east side of the east room of the basement. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 86, Lake Placid, N. Y. (1909).—Lake Placid Inn, storeroom in the east comer of the basement directly below, 
he hotel dining room. The case was mounted on a low concrete pier. 

No. 87, Potsdam, N. Y. (1909).—Clarkson School of Technology, photometric room, on the ground floor, directly 
north of north entrance to the furnace room. The case was mounted on a stone pier composed of two large stone blocks 
resting on the concrete floor. 

No. 88, Wilson, N. Y. (1909).—Wilson High School, middle furnace room in the center of the basement. The case 
was mounted on a low concrete pier. 

No. 89, Alpena, Mich. (1909).—City hall, alcove under steps at the northwest end of the basement hall and just 
to the left of the entrance to the office of chief of police. The case was mounted on the concrete floor. 

No. 90, Virginia Beach, Va. (1911).—Arlington Hotel, temporary room constructed in the northeast corner of the 
basement of the north wing. The case was mounted on low concrete pier which in turn rested on the brick floor. 

No. 91, Durham, N. C. (1911).—Trinity College, Academic Building, small room in middle of east end of basement. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 92, Femandina, Fla. (1911).—Federal Building, northeast corner of Center and Fourth Streets, coal room in 
the southeast corner of the basement. The case was mounted on three bricks each cemented to the concrete floor. 

No. 93, Wilmer, Ala. (1911 and 1915).—Abandoned ice house at the east end of the post office, which is located at 
the point where the main road from the railway station turns to the westward. The case was mounted on a brick pier. 

No. 94, Aliceville, Ala. (1911).—Constructed pendulum room located on a public highway or West First Street, 47.5 
feet north of the building line on the north side of Third Avenue and 23 feet west of the building line on the east side 
of West First Street. The case was mounted on a concrete pier. 

No. 95, New Madrid, Mo. (1911).—High-school building, furnace room in the basement at the west end of the 
west wing. The case was mounted on three bricks each cemented to the concrete floor. 

No. 96, Mena, Ark. (1911).—High-school building, southwest corner of Eleventh Street and Magnolia Avenue, 
furnace room in the basement under the east end of the building. The case was mounted on three bricks each cemented 
to the concrete floor. 

No. 97, Nacogdoches, Tex. (1911).—M. E. Church on Hospital and Pecan Streets, small room off the west end of 
the vestry in the north end of the basement. The case was mounted with two bricks under each footplate cemented 
together and to the concrete floor. 

No. 98, Alpine, Tex. (1911).—Higli-school building at the foot of Sixth Street, small basement room in the middle 
of the west side of the building directly under the west entryway. The case was mounted with two bricks under each 
footplate cemented together and to the concrete floor. 

No. 99, Farwell, Tex. (1911).—Farwell Hotel at the southwest corner of the public square, basement room in south¬ 
west corner of the building, which is unoccupied. The case was mounted with two bricks under each footplate cemented 
together and to the concrete floor. 

No. 100, Guymon, Okla. (1911).—Summers Building, small inside room off the northeast comer of the barber shop. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 101, Helenwood, Tenn. (1911).—Observatory pendulum room on the premises of Mr. Duncan, directly opposite 
the railroad station at Helenwood, 40 feet south of Mr. Duncan’s north fence line and 16 feet west of his east fence line 
and about 400 feet east of the railroad station. The case was mounted on a pier of concrete building blocks. 

No. 102, Cloudland, Tenn. (1909).—Summit of Roan Mountain, Old Cloudland Hotel, northwest corner of the 
southeast room on the ground floor. The case was mounted on a concrete pier. 

No. 103, Hughes, Tenn. (1909 and 1911).—Observatory pendulum room on Lewis Hughes’s farm, in the corner of 
his pasture lot, and about 75 feet due east of the north end of his house, w'hich is the first house on the east side of Cove 
Creek just south of its junction with Doe River, V/i miles east of Hughes Gap and 1% miles west by south from 
Burbank. The case was mounted on a concrete pier. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


181 


No. 104, Charleston, W. Va. (1911).—High-school building on Quarrier Street near Broad Street, boys’ coat room 
in the basement under the boys’ entrance on the northwest side of the building. The case was mounted with two bricks 
under each footplate cemented together and to the concrete floor. 

No. 105, State College, Pa. (1911). Chemistry-Physics Building of Pennsylvania State College, photometer room 
in the basement. The case was mounted with two bricks under each footplate cemented together and to the concrete 
floor. 

No. 106, Fort Kent, Me. (1909).—Dickey Hotel, in the north corner of the basement directly under the hotel office. 
The case was mounted on a low concrete pier. 

No. 107, Prentice, Wis. (1911).—Public-school building, room in the basement under the east entrance to the build¬ 
ing. The case was mounted on a concrete pier. 

No. 108, Fergus Falls, Minn. (1911).—High-school building on Cavour Street between Court and Union Streets, 
girls’ entrance to the basement from the north side of the building. The oase was mounted with two bricks under 
each footplate cemented together and to the concrete floor. 

No. 109, Sheridan, Wyo. (1911).—County courthouse, southwest corner of South Main and West Burkill Streets, 
room in the northwest corner of the basement known as storage vault No. 2. The case was mounted with two bricks 
under each footplate cemented together and to the concrete floor. 

No. 110, Boulder, Mont. (1911).—Pub he school south of the courthouse, boys’ toilet in the southeast corner of the 
basement. The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. Ill, Skykomish, Wash. (1911).—Public-school building, boiler room. The case was mounted with two bricks 
under each footplate cemented together and to the concrete floor. 

No. 112, Olympia, Wash. (1911).—Washington School building on West Fifth and Quince Streets, boys’ toilet in 
the basement east of the main entrance on the north side of the building. The case was mounted with two bricks 
under each footplate cemented together and to the concrete floor. 

No. 113, Heppner, Oreg. (1911).—Morrow County courthouse, storage room in the middle of the basement. The 
case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 114, Truckee, Cal. (1911).—High-school building, temporary room constructed in the northeast corner of the 
southern half of the basement. The case was mounted on a concrete pier. 

No. 115, Winnemucca, Nev. (1911).—Store owned by H. Warren, on Bridge Street, next to the fire station, furnace 
room in the basement. The case was mounted with two bricks under each footplate cemented together and to the 
concrete floor. 

No. 116, Ely, Nev. (1911).-—Graded-sehool building, storage room in the northeast corner of the basement. The 
case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 117, Guernsey, Wyo. (1911).-—Guernsey Hotel, basement room about the middle of the south side. The case 
was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 118, Pierre, S. Dak. (1911).—High-school building opposite the Capitol, storage room in basement between 
the toilet and the gymnasium. The case was mounted with two bricks under each footplate cemented together and to 
the concrete floor. 

No. 119, Fort Dodge, Iowa (1911).—High-school building, storage room about the center of the basement. The 
case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 120, Keithsburg, III. (1911).—Public-school building, temporary room constructed in the basement under the 
west part of the building. The case was mounted with two bricks under each footplate cemented together and to 
the concrete floor. 

No. 121, Grand Rapids, Mich. (1911).—Smaller building on the northwest corner of the new high-school grounds, 
at Fountain and North Prospect Streets, boiler room in the northwest corner of the basement. The case was mounted 
on the concrete floor. 

No. 122, Angola, Ind. (1911).—Public-school building on East Water Street between South Wayne and South 
Martha Streets, storage room in the southeast corner of the basement. The case was mounted with two bricks under 
each footplate cemented together and to the concrete floor. 

No. 123, Albany, N. Y. (1911 and 1914).—Public School No. 24, at Delaware and Dana Avenues, janitor’s store¬ 
room in the basement, under the boys’ entrance on the east side of the building. The case was mounted with two 
bricks under each footplate cemented together and to the concrete floor. 

No. 124, Port Jervis, N. Y. (1911).—Church Street School building, basement room about the middle of the south¬ 
east side of the building. The case was mounted with two bricks under each footplate cemented together and to the 
concrete floor. 

No. 125, Atlantic City, N. J. (1914).—New high school, corner of Atlantic and Massachusetts Avenues, northwest 
corner of the dark storeroom in the basement, directly under the steps at the Atlantic Avenue entrance. The case 
was mounted on a slate slab 3 inches thick cemented to the floor. 

No. 126, Bridgehampton, N. Y. (1914).—High-school building, near the north side of the laboratory room in the 
basement. The case was mounted on the concrete floor. 

No. 127, Chatham, Mass. (1914).—In northwest corner of the small concrete fish house belonging to A. E. Thatcher 
on the north side of the mill pond. The case was mounted on the concrete floor. 

No. 128, Rockland, Me. (1914).—Home of Fred Burpee, at 104 Limerock Street, in the northwest corner of the 
south extension of the basement or cellar. The case was mounted on the concrete floor. 


182 


U. S. COAST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


No. 129, Lancaster , N. H. (1914).—High school, near the intersection of Main and School Streets, in the basement 
near the northwest corner of the southwesterly room used as a bath and dressing room for the gymnasium. The case 
was mounted on the concrete floor. 

No. 130, Whitehall, N. Y. (1914).—Armory at the corner of Willian and Daultney Streets, near the northwest 
corner of the dark room in the basement. The case was mounted with one brick under each footplate cemented to the 
concrete floor. 

No. 131, Little Falls, N. Y. (1914).—Benton Hall School, on the east side of the park, at the corner of Alexander 
and Waith Streets, in a temporary room constructed in the most northwesterly room of the basement. r I he case was 
mounted on the concrete floor. 

No. 132, Watertown, N. Y. (1914).—High school, on Sterling Street between Washington and Jay Streets, in the 
carpenter shop in the basement. The case was mounted on the concrete floor. 

No. 133, Southport, N. Y. (1914).—In the basement of a small store on Pennsylvania Avenue used as a storeroom 
by Sargent & Sage, whose grocery store is the next building east at the corner of Pennsylvania and ( aton Avenues. 
The case was mounted on a pier built of brick, stone, and plaster of Paris. 

No. 134, Erie, Pa. (1914).—Public School No. 2, at the corner of Seventh and Holland Streets, in the basement 
storeroom under the steps at the south entrance. The case was mounted on the concrete floor. 

No. 135, Parkersburg, W. Va. (1914).—Post office, in the southeast corner of the small room in the northeast corner 
of the basement. The case was mounted with one brick under each footplate cemented to the concrete floor. 

No. 136, Columbus, Ohio (1914).—Franklin County Memorial Hall, on East Broad Street, in the northeast corner 
of a triangular-shaped room called the kitchen, in the basement back of the stage. The case was mounted with one 
brick under each footplate cemented to the concrete floor. 

No. 137, Indianapolis, Ind. (1914).—Post office, in a small triangular-shaped room on the Meridian Street side of 
the basement used as a storeroom by the engineer of the building and directly across the hall from the west elevator. 
The case was mounted on the concrete floor. 

No. 138, Springfield, III. (1914).—Edwards Public School, at the corner of Lawrence Avenue West and Edwards 
Street, in a room near the center of the north front of the basement. The case was mounted on the concrete floor. 

No. 139, Lebanon, Mo. (1914).—New high school, in the furnace room about 2 feet from the corner of the brick¬ 
work supporting the boiler. The case was mounted on the concrete floor. 

No. 140, Joplin, Mo. (1914).—Post office, a small room with a sloping ceiling under the stairway in the northeast 
corner of the basement. The case was mounted on the concrete floor. 

No. 141, Fort Smith, Ark. (1914).—Courthouse, in the northeast corner of the room used as a test room for cement, 
etc., by the city engineer, in the southeast corner of the basement. The case was mounted on the concrete floor. 

No. 142, Texarkana, Ark. (1914).—Post office, in the northwest room of the basement of the north wing. The case 
was mounted on the concrete floor. 

No. 143, Hot Springs, Ark. (1914).—Garland County courthouse, in the north corner room of the ground floor. The 
case was mounted on the concrete floor. 

No. 144, Alexandria, La. (1914).—City hall, in one of the small closets under the steps on the northwest side of the 
basement and just to the left of the short flight of steps leading to the main hall of the basement. The case was mounted 
on the concrete floor. 

No. 145, Laurel, Miss. (1914).—Silas Gardner School, in a room on the north side of the basement, the first room 
to the left when entering the basement at the east door and just across the hall from the domestic-science kitchen. The 
case was mounted on the concrete floor. 

No. 146, Richmond, Va. (1915).—Post office, in a room near the center of the south side of the basement used as a 
storeroom by the internal-revenue department. The case was mounted with one brick under each footplate cemented 
to the concrete floor. 

No. 147, Emporia, Va. (1915).—The station is in the county courthouse. Two sets of observations were made, the 
first in the office of the commissioner of revenue in the south wing of the courthouse and the second in the southeast 
corner of the mayor’s office, which is the next room. For the first set the case was mounted on the wooden floor and 
for the second set the case was mounted on the concrete floor. 

No. 148, Greenville, N. C. (1915).—Proctor Hotel, on the corner of Evans and Third Streets, in room No. 2 of the 
higher or back level of the basement, the second room from the steps leading from the lower or front part of the base¬ 
ment and on the left side of the hallway. The case was probably mounted on the concrete floor. 

No. 149, Wilmington, N. C. (1915).—County courthouse at the intersection of Third and Princess Streets, in a room 
in the basement once used as a storeroom for disinfectants by the city health officer. It is on the side of the basement 
toward Princess Street and the last room but one on the left side of the corridor at right angles to Third Street. The 
case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 150, Cheraw, S. C. (1915).—Hotel Covington, in a back room on the first floor, the second room from the north¬ 
west end of the building and directly opposite the office of Dr. Purvis. The room is separated from the next one by 
a partition two-thirds of the way to the ceiling. The case was probably mounted on the concrete floor. 

No. 151, Charlotte, N. C. (1915).—United States assay office, in a small room in the east corner of the basement. 
The case was probably mounted on the concrete floor. 

No. 152, Asheville, N. C. (1915).—Post office, in the northeast corner room of the basement which has two small 
windows opening on Haywood Street. The case was mounted with two bricks under each footplate cemented together 
and to the concrete floor. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 


183 


No. 153, Cleveland, Tenn. (1915).—Post office, in the southwest comer of the basement, in a room used as a rest 
room for the rural carriers. The case was mounted with two bricks under each footplate cemented together and to 
the concrete floor. 

No. 154, Winston-Salem, N. C. (1915).—High school on Cherry Street at the head of Third Street, in the southwest 
corner of the basement in a room used as a storage room. The case was probably mounted on the concrete floor. 

No. 155, Knoxville, Tenn. (1915).—Western Union office building, on Gay Street near Vine Street, in the basement 
in a room used as a storeroom by the linemen and about 10 feet from the foot of the stairs leading down from the main 
office. The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 156, Bristol, Va. (1915).—Courthouse and city hall, in a room on the south side of the basement next to the 
southeast corner room. The case was mounted with two bricks under each footplate cemented together and to the 
concrete floor. 

No. 157, Homestead, Fla. (1915).—High school, in a temporary room constructed on the north end of the west 
porch. The case was mounted with two bricks under each footplate cemented together and to the concrete floor of 
the porch. 

No. 158, Sebring, Fla. (1915).—Kiln for drying lumber, about 40 meters northeast of the electric-light plant and 
100 meters northeast of the Atlantic Coast Line Railway station. The case was mounted on a pier made of concrete 
blocks cemented together, with two bricks under each footplate cemented together and to the top of the pier. 

No. 159, Titusville, Fla. (1915).—Small office belonging to J. S. Daniels near the northwest corner of Palm and Julia 
Streets. The case was mounted on a pier made of concrete blocks cemented together, with two bricks under each 
footplate cemented together and to the top of the pier. 

No. 160. Leesburg, Fla. (1915).—George W. Wrenneck Building, at the corner of Main and Seventh Streets, in the 
southwest corner of the back room. The case was mounted with two bricks under each footplate cemented together 
and to the concrete floor. 

No. 161, Cedar Keys, Fla. (1915).—House belonging to J. B. Lutterdah, at the northeast corner of Fifth and D 
Streets, in the northwest corner of the south basement room. The case was mounted on a brick pier with two bricks 
under each footplate cemented together and to the top of the pier. 

No. 162, Macon, Ga. (1915).—Post office, near the window of the engineer’s room in the basement. The case 
was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 163, Albany, Ga. (1915).—Grammar school at the corner of Broad and Madison Streets, in the northwest comer 
of the janitor’s storeroom in the basement. The case was mounted with one brick under each footplate cemented to 
the concrete floor. 

No. 164, Pensacola, Fla. (1915).—Customhouse and post office, in the northeast corner of the customhouse store¬ 
room in the basement. The case was mounted with two bricks under each footplate cemented together and to the 
concrete floor. 

No. 165, Opelika, Ala. (1915).—New brick store on Avenue A, owned by Mrs. Josephine Denniston and rented by 
J. Lem Satterwhite, in the southeast end of the basement. The case was mounted with two bricks under each foot¬ 
plate cemented together and to the concrete floor. 

No. 166, Huntsville, Ala. (1915).—United States courthouse and post office, in the easternmost room in the base¬ 
ment. The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 167, Arkansas City, Ark. (1915).—Courthouse, in the west corner of the grand jury room. The case was mounted 
with two bricks under each footplate cemented together and to the concrete floor. 

No. 168, Memphis, Tenn. (1915).—Customhouse and post office, in the northeast corner of the northeast room in 
the basement. The case was mounted with two bricks under each footplate cemented together and to the concrete 
floor. 

No. 169, Mammoth Spring, Ark. (1915).—Old Fulton County Bank Building, owned by the Citizens Bank of 
Mammoth Spring, in a small room used for ice storage in the southwest corner of the north basement room. The case 
was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 170, Hopkinsville, Ky. (1915).—Custonhouse and post office, in the southeast corner of the northeast room of 
the basement. The case was mounted with two bricks under each footplate cemented together and to the concrete 
floor. 

No. 171, Danville, Ky. (1915).—Customhouse and post office, near the center of the north end of the room used as a 
coal bin in the northeast corner of the basement. The case was mounted with two bricks under each footplate cemented 
together and to the concrete floor. 

No. 172, Clifton Forge, Va. (1915).—Courthouse and post office, in the north end of the storeroom near the center 
of the west side of the basement. The case was mounted with two bricks under each footplate cemented together and 
to the concrete floor. 

No. 173, Greenville, Ala. (1915).—Courthouse, in the west end of the coal bin in the boiler room in the basement. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 174, Birmingham, Ala. (1915).—United States customhouse and post office at the northeast corner of Second 
Avenue and Eighteenth Street, in the janitor’s office in the basement. The case was mounted with two bricks under 
each footplate cemented together and to the concrete floor. 

No. 175, Lexington, Va. (1915).—Post office at the corner of Lee Avenue and Nelson Street, in the southwest end 
of the storeroom near the center of the northeast side of the basement. The case was mounted with two bricks under 
each footplate cemented together and to the concrete floor. 


184 


U. S. C04ST AND GEODETIC SURVEY SPECIAL PUBLICATION NO. 40. 


No. 176, Prestonsburg, Ky. (1915).—The Bank Josephine, on Main Street, at the foot of the bridge over the Big 
Sandy River, in the northwest corner of the southwest room in the basement. The case was mounted with two bricks 
under each footplate cemented together and to the concrete floor. 

No. 177, Traverse City, Mich. (1915).—Post office, in storeroom in the basement. The case was mounted with two 
bricks under each footplate cemented together and to the concrete floor. 

No. 178, Seney, Mich. (1915).-—Bank of the Boggott, Bacheller & Cool Banking Co., in the vault. The case was 
mounted on the concrete floor. 

No. 179, Oconto, Wis. (1915).—High school on School Street, in the mechanical drawing room in the south corner 
of the basement. The case was mounted with two bricks under each footplate cemented together and to the concrete 
floor. 

No. 180, Grand Rapids, Wis. (1915).—Bandelin Hotel on Grand Avenue, in the basement near the middle of the 
east side. The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 181, Winona, Minn. (1915).—Post office, in the northeast corner room of the basement. The case was mounted 
on the brick floor, with one paving brick under each footplate. 

No. 182, Baldwin, Wis. (1915).—Town Hall, in the rest room in the basement at the foot of the stairs leading from 
the main entrance of the building. The case was mounted with two bricks under each footplate cemented together 
and to the concrete floor. 

No. 183, Cumberland, Wis. (1915).—High-school building, in the boiler room in the basement. The case was 
mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 184, Cambridge, Minn. (1915).—High-school building, in the west part of the boiler room in the basement. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 185, Brainerd, Minn. (1915).—Post office at northwest corner of Maple and Sixth Streets, in a room about 
midway of the west side of the basement. The case was mounted with two.bricks under each footplate cemented 
together and to the concrete floor. 

No. 186, Aberdeen, S. Dak. (1915).—Post office and courthouse, in the north end of the small storeroom at the north 
end of the basement. The case was mounted with a small concrete block under each footplate cemented to the concrete 
floor. 

No. 187, Faith, S. Dak. (1915).—W. C. Meyer’s residence, about 260 meters west-southwest from the Chicago, 
Milwaukee & St. Paul Railway Station, in the northwest room of the basement. The case was mounted with a small 
concrete block under each footplate cemented to the concrete floor. 

No. 188, Marmarth, N. Dak. (1915).—Allison Building, on the corner of Main and First Streets, in the west end 
of a small storeroom in the basement directly beneath the post office. The case was mounted with a small concrete 
block under each footplate cemented to the concrete floor. 

No. 189, Towner, N. Dak. (1915).—McHenry County courthouse, in the west end of the vault in the basement. 
The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 190, Crosby, N. Dak. (1915).—Crosby graded school, in the northwest room in the basement. The case was 
mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 191, Crookston, Minn. (1915).—Franklin School, in the east part of the basement. The case was mounted 
with two bricks under each footplate cemented together and to the concrete floor. 

No. 192, Poplar Mont. (1915).—Poplar public school in the northeast part of the town, in the east room in the 
basement. The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 193, Miles City, Mont. (1915).—Lincoln School, on Lake Street, in the south part of the town, in the south end 
of the west storeroom in the basement. The case was mounted with a small concrete block under each footplate 
cemented to the concrete floor. 

No. 194, Huntley, Mont. (1915).—Huntley Hotel, north-northwest of the railway station, in the southeast corner 
of the basement room under the south part of the hotel. The case was mounted with a small concrete block under 
each footplate cemented to the concrete floor. 

No. 195, Lander, Wyo. (1915).—Post office and courthouse, in the south end of the storeroom in the south comer of 
the basement. The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 196, Fanbault, Minn. (1915).—Central School, in the southeast corner room of the basement. The case was 
mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 197, St. James, Minn. (1915).—County courthouse, in the basement midway of the north side of the building. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 198, Edgemont, S. Dak. (1915).—Public-school building, in the southwest corner of the southeast room in the 
basement. The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 199, Dawson, Minn. (1915).—High-school building, in the dark room in the basement. The case was mounted 
tvith two bricks under each footplate cemented together and to the concrete floor. 

No. 200, Cokalo, Minn. (1915).—High school, in the basement under the central part of the east side of the building. 
The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 201, Wasta, S. Dak. (1915.)—Residence of James Trask on the east side of the street one block west and two 
blocks north from the railway station, in the northwest corner of the cellar under the southeast corner of the house. 
The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 


INVESTIGATIONS OF GRAVITY AND ISOSTASY. 185 

No. 202, Mooiaoft, Wyo. (1915).—Public-school building, on the south side of the east room in the basement. 
The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 203, Duluth, Minn. (1915).—County courthouse, in a room known as the connecting hall in the basement under 
the center of the building. The case was mounted with two bricks under each footplate cemented together and to the 
concrete floor. 

No. 204, Osage, Iowa (1915).—High school, in the basement near the middle of the south side of the building and 
directly under the galvanized-iron air duct. The case was mounted with two bricks under each footplate cemented 
together and to the concrete floor. 

No. 205, Randolph, Nebr. (1915).—Public school near the Burlington Railway station, in the southwest corner of 
a temporary room constructed in the west end of the southernmost ventilating room in the basement under the east 
side of the building. The case was mounted with a small concrete block under each footplate cemented to the concrete 
floor. 

No. 206, Valentine, Nebr. (1915).—Public school, in the southeast corner of the southeast room in the basement. 
The case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 207, Wheeling, W. Va. (1915).—German Bank Building, in the basement under the Western Union Telegraph 
office. The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 208, Leon, Iowa (1915).—North School, in the south side of the northwest room on the ground floor. The 
case was mounted with a small concrete block under each footplate cemented to the concrete floor. 

No. 209, Laurel, Md. (1915).—Residence of Col. Frank E. Little on Main Street about 10 minutes walk from the 
Baltimore & Ohio Railway station, in the east corner of the easternmost room in the basement. The case was mounted 
with a small concrete block under each footplate cemented to the concrete floor. 

No. 210, Harrisburg, Pa. (1915).—Central High School, in the basement near the center of the north side of the 
building. The cast was mounted with two bricks under each footplate cemented together and to the concrett floor. 

No. 211, Pittsburg, Pa. (1915).—Second Ward School on Sherman Avenue just north of North Avenue in the 
north-side section of Pittsburgh, in the basement under the east front of the building. The case was mounted with 
two bricks under each footplate cemented together and to the concrete floor. 

No. 212, Rockville, Md. (1915).—High school, in the north end of a small room formerly used as a printing shop in 
the basement under the north side of the building. The case was mounted with a small concrete block under each 
footplate cemented to the concrete floor. 

No. 213, Upper Marlboro, Md. (1915).—Masonic Hall on the south side of Main Street about 80 meters west of the 
courthouse, in the west side of the southeast room in the basement. The case was mounted with a small concrete 
block under each footplate cemented to the concrete floor. 

No. 214, Fairfax, Va. (1915).—Bungalow belonging to tffi Rural Homes Development Co. about 300 meters west- 
northwest from the residence of E. A. Capen, in the southwest corner of the basement. The case was mounted with a 
small concrete block under each footplate cemented to the concrete floor. 

No. 215, Crisfield, Md. (1915).—Residence of J. H. Riggin, 101 South Somerset Avenue, in the rear part of the 
basement. The case was mounted with two bricks under each footplate cemented together and to the concrete floor. 

No. 216, Fredericksburg, Va. (1915).—Post office, storeroom in the basement under the north side of the building. 
The case was mounted on the concrete floor. 

No. 217, Dover, Del. (1915).—Wilmington Conference Academy, in the basement under the gymnasium at the 
middle of the north side of the building. The case was mounted with two bricks under each footplate cemented 
together and to the concrete floor. 

No. 218, North Tamarack near Calumet, Mich. (1902).—Observations were made at three different levels at North 
Tamarack Mine, at the surface of the ground, at a depth of 1200 feet, and at a depth of 4600 feet. The two stations 
below the ground were occupied by Prof. F. W. McNair, of the Michigan College of Mines. His results are not pub¬ 
lished here. A temporary pendulum room was probably used for the surface observations. The case was mounted 
on a masonry pier. 

No. 219 Hagerstown, Md. (1915).—Post office, in the northeast corner of the boiler room in the northwest corner of 
the basement. The case was mounted with a small concrete block under each foot plate cemented to the concrete floor. 



































. 













































































INDEX TO THE PUBLICATIONS CONTAINING ABSTRACTS OF RESULTS AND DESCRIPTIONS 

OF GRAVITY STATIONS IN THE UNITED STATES 


Name of station 


Aberdeen, S. Dak. 

Albany, Ga. 

Albany, N. Y. 

Alexandria, La. 

Alicevilie, Ala. 

Alpena, Mich. 

Alpine, Tex. 

Angola, Ind. 

Apalachicola, Fla. 

Arkansas City, Ark. 

Asheville, N. C. 

Astoria, Oreg. 

Atlanta, Ga. 

Atlantic City, N. J. 

Austin, Tex. (capitoi) ... 
Austin, Tex. (university) 

Baldwin, Wis. 

Baltimore, Md. 

Beaufort, N. C. 

Birmingham, Ala. 

Bismarck, N. Dak. 

Boise, Idaho. 

Boston, Mass. 

Boulder, Mont. 

Brainerd, Minn. 

Bridgehampton, N. Y 
Bristol, V a... 

Calais, Me. 

Cambridge, Mass. 

Cambridge, Minn. 

Cedar Keys, Fla. 

Charleston, S. C. 

Charleston, XXL Va. 

Charlotte, N. C. 

Charlottesville, A 7 a. 

Chatham, Mass. 

Cheraw, S. C. 

Chicago, Ill. 

Cincinnati, Ohio. 

Cleveland, Ohio. 

Cleveland, Tenn. 

Clifton Forge, Va. 

Cloudland, Tenn. 

Cokato, Minn. 

Colorado Springs, Colo.... 

Columbia, Tenn. 

Columbus, Ohio. 

Compton, Cal. 

Crisfleld, Md. 


No. of 
station 

Observer 

Year ob¬ 
served 

Descrip¬ 
tion, this 
publica¬ 
tion 

This 

publica¬ 

tion 

Report, 
1891, 
App. 15 

Abstract 

Report, 
1894, 
App. 1 

Report, 
1897, 
App. 6 

Report, 
1898-99, 
App. 4 




Page 

Page 

Page 

Page 

Page 

Page 

186 

C. L. Gamer. 

1915 

184 

172 





163 

.do. 

1915 

183 

170 





123 

T. L. Warner. 

1911 

181 

157 





144 

J. D. Powell. 

1914 

182 

160 





94 

H. D. King. 

1911 

180 

153 





89 

W. H. Burger. 

1909 

180 

147 





98 

H. D. King. 

1911 

180 

154 





122 

T. L. Warner. 

1911 

181 

157 





4 

W. H. Burger. 

1909 

177 

145 





167 

C. L. Garner. 

1915 

183 

171 





152 

J. D. Powell. 

1915 

182 

161 





80 

H. D. King. 

1910 

180 

151 





15 

G. B. Putnam .. 

1896 

177 




306 


125 

C. L. Gamer. 

1914 

181 

167 





10 

G. R. Putnam_ 

1895 

177 




304 


11 

.. do.. 

1895 

177 




304 


182 

.T. D. Powell_ 

1915 

184 

163 










App. 2, 



23 

E. D. Preston... 

1893 

178 



61 (of 








’94.) 



18 

W. H. Burger_ 

1909 

177 

145 





174 

C. L. Gamer _ 

1915 

183 

170 





76 

H. D. King 

1910 

179 

151 





79 

.do. _ 

1910 

180 

151 





29 

G. R. Putnam 

1894 

178 



31 



110 

T. R. Warner_ . 

1911 

181 

156 





185 

J D Powell. 

1915 

184 

164 





126 


1914 

181 

167 





155 


1915 

183 

162 





31 

Cl P, Putnam 

1895 

178 




305 


30 


1894 

178 



31 



184 


1915 

184 

164 





161 

n. R. Garner _ 

1915 

183 

169 





17 

G R Putnam 

1896 

177 




306 


104 

T. R. Warner 

1911 

181 

155 





151 


1915 

182 

161 





19 

Cl R Putnam 

1894 

177 



33 



127 

C. R. Garner __ 

1914 

181 

167 





150 


1915 

182 

161 





36 


1894 

178 



34 



34 

.do ... 

1894 

178 



37 



33 


1894 

178 

. 


34 



153 


1915 

183 

162 





172 


1915 

183 

172 





102 


1909 

180 

146 





200 


1915 

184 

165 





42 


1894 

178 



36 



14 


1909 

177 

145 





136 


1914 

182 

159 





66 


1910 

179 

149 





215 

J. D. Powell. 

1915 

185 

166 






187 


































































































































































































188 


INDEX TO PUBLICATIONS, 


Name of station 

No. of 
station 

Observer 

Year ob¬ 
served 

Descrip¬ 
tion, this 
publica¬ 
tion 


• 

Abstract 

This 

publica¬ 

tion 

Report, 
1891, 
App. 15 

Report, 
1894, 
App. 1 

Report, 
1897, 
App. 6 

Report, 
1898-99, 
App. 4 





Page 

Page 

Page 

Page 

Page 

Page 


191 

.T. D. Powell 

1915 

184 

163 






190 


1915 

184 

173 





Onmbflriand, Wis ._ 

183 

J. D. Powell.. 

1915 

184 

163 





Danville, Ky. 

171 

C. L. Garner. 

1915 

183 

171 





Dawson, Minn. 

199 

J. D. Powell . 

1915 

184 

165 





Deer Park, Md. 

20 

G. R. Putnam.... 

1894 

177 



34 



Denison, Tex. 

73 

W. H. Burger. 

1910 

179 

150 





Denver, Colo. 

44 

G. R. Putnam 

1894 

178 



36 



Dover, Del. 

217 

J. D. Powell. 

1915 

185 

166 





Duluth, Minn. 

203 

.do. 

1915 

185 

165 





Durham, N. C. 

91 

H. D. King . 

1911 

180 

153 





Edgemont, S. Dak . 

198 

C. L. Garner . 

1915 

184 

174 





Ellsworth, Kans . 

40 

G. R. Putnam 

1894 

178 



37 



El Paso, Tex . 

63 

W. II. Burger . 

1910 

179 

149 





Ely, Minn. 

58 

.do. 

1909 

179 

147 





Ely, Nev. 

11G 

T. L. Warner. 

1911 

181 

156 





Emporia, Va . 

147 

J. D. Powell . 

1915 

182 

161 





Erie, Pa . 

134 

C. L. Garner . 

1914 

182 

168 





Fairfax, Va . 

214 

. do . 

1915 

185 

175 





Faith, S. Dak . 

187 

. do . 

1915 

1S4 

173 





Faribault, Minn . 

196 

J. D. Powell . 

1915 

184 

164 





Farwell, Tex . 

99 

H. D. King . 

1911 

180 

154 





Fergus Falls, Minn . 

108 

T. L. Warner . 

1911 

181 

155 





Fernandina, Fla . 

92 

H. D. King. 

1911 

180 

153 





Fort Dodge, Iowa . 

119 

T. L. Warner . 

1911 

181 

157 





Fort Kent, Me . 

106 

W. H. Burger . 

1909 

181 

146 





Fort Smith, Ark . 

141 

J. D. Powell . 

1914 

182 

159 





Fredericksburg, Va . 

216 

. do . 

1915 

185 

166 





Gallup, N. Mex . 

70 

W. H. Burger . 

1910 

179 

150 





Galveston, Tex . 

7 

G. R. Putnam _ 

1895 

177 




304 


Goldfield, Nev . 

67 

W. H. Burger . 

1910 

179 

149 




Grand Canyon, Ariz . 

69 

. do . 

1910 

179 

149 





Grand Canyon, Wyo . 

50 

G. R. Putnam. ... 

1894 

178 



35 



Grand Junction, Colo . 

46 


1894 

178 



36 



Grand Rapids, Mich. 

121 

T. L, Warner. 

1911 

181 

157 




Grand Rapids, Wis . 

180 

J. D. Powell. 

1915 

184 

163 





Green River, Utah . 

47 

G. R. Putnam_ 

1894 

178 



35 



Greenville, Ala . 

173 

C. L. Garner. 

1915 

183 

171 




Greenville, N. C . 

148 

J. D. Powell. 

1915 

182 

161 





Guernsey, Wyo . 

117 

T. L. Warner. 

1911 

181 

157 





Gunnison, Colo. . 

45 

G. R. Putnam.... 

1894 

178 



36 



Guymon, Okla . 

100 

H. D. King. 

1911 

180 

154 




Hagerstown, Md . 

219 

C. L. Garner. 

1915 

185 

176 





Harrisburg, Pa . 

210 

J. D. Powell. 

1915 

185 

165 





Helenwood, Term . 

101 

T. L. Warner. 

1911 

180 

154 





Heppner, Oreg. 

113 

.do. 

1911 

181 

156 





Hinsdale, Mont. 

77 

H. D. King. 

1910 

179 

151 





Hoboken, N. J. 

26 

T. C. Mendenhall.. 

1891 

178 


556-557 




Homestead, Fla. 

157 

C. L. Gamer. 

1915 

183 

169 




Hopkinsville, Ky . 

170 

.do . 

1915 

183 

171 





Hot Springs, Ark . 

143 

J. D. Powell. 

1914 

182 

160 





Hughes, Tenn . 

103 

W. H. Burger. 

1909 

180 

146 





Do . 


T. L. Warner . 

1911 

ISO 

155 





Huntley, Mont . 

.194 

C. L. Gamer. 

1915 

184 

174 





Huntsville, Ala . 

166 


1915 

183 

170 









































































































































































































INDEX TO PUBLICATIONS, 


189 


Name of station 

No. of 
station 

Observer 

Year ob¬ 
served 

Descrip¬ 
tion, this 
publica¬ 
tion 

This 

publica¬ 

tion 

Report, 
1891, 
App. 15 

Abstract 

Report, 
1894, 
App. 1 

Report, 
1897, 
App. 6 

Report, 
1898-99, 
App. 4 





Page 

Page 

Page 

Page 

Page 

Page 

Indianapolis, Ind. 

137 

J. D. Powell. 

1914 

182 

159 





Iron River, Mich. 

57 

W. H. Burger. 

1909 

179 

147 





Do. 


n. D. King. 

1910 

179 

150 





Ithaca, N. Y. 

32 

G. R. Putnam.... 

1894 

178 



32 



Joplin, Mo. 

140 

J. D. Powell. 

1914 

182 

159 





Kansas City, Mo. 

39 

G. R. Putnam.... 

1894 

178 



37 



Keithsburg, Ill. 

120 

T. L. Warner. 

1911 

181 

157 




Kerrville, Tex. 

62 

W. H. Burger. 

1910 

179 

149 





Key West, Fla. 

1 

G. R. Putnam_ 

1896 

177 




305 


Knoxville, Tenn. 

155 

J. D. Powell. 

1915 

183 

162 





Lake Placid, N. Y. 

86 

W. H. Burger. 

1909 

180 

147 





Lancaster, N. H. 

129 

C. L. Garner. 

1914 

182 

167 





Lander, Wyo. 

195 

.do. 

1915 

184 

174 





Laredo, Tex. 

9 

G. R. Putnam_ 

1895 

177 




304 


Las Vegas, N. Mex. 

71 

W. H. Burger. 

1910 

179 

150 





Laurel, Md. 

209 

C. L. Garner. 

1915 

185 

175 





Laurel, Miss. 

145 

J. D. Powell. 

1914 

182 

160 





Lead, S. Dak. 

75 

H. D. King. 

1910 

179 

151 





Lebanon, Mo. 

139 

J. D. Powell. 

1914 

182 

159 





Leesburg, Fla. 

160 

C. L. Garner. 

1915 

183 

169 





Leon, Iowa. 

208 


1915 

185 

175 





Lexington, Va. 

175 

.do. 

1915 

183 

172 





Little Falls, N. Y. 

131 

.do. 

1914 

182 

168 





Little Rock, Ark. 

13 

G. R. Putnam_ 

1896 

177 




306 


Lower Geyser Basin, Wyo. 

52 

.do. 

1894 

178 



35 




12 

W. H. Burger. 

1909 

177 

145 






16 

.do. 

1909 

177 

145 





Maoon, Gfl . 

162 

C. L. Garner. 

1915 

183 

170 






37 

E. Smith. 

1906 

178 






Mammoth Spring, Ark. 

169 

C. L. Garner. 

1915 

183 

171 






188 

.do. 

1915 

184 

173 






168 

.do. 

1915 

183 

171 






96 

H. D. King. 

1911 

180 

154 






193 

C. L. Garner _ 

1915 

184 

173 






74 

H. D. King. 

1910 

179 

151 






60 

W. H. Burger. 

1909 

179 

147 






202 

C. L. Garner. 

1915 

1S5 

174 






55 

T. C. Mendenhall. 

1891 

179 


549- 550 





97 

H. D. King. 

1911 

180 

154 






95 

.do. 

1911 

180 

153 






5 

G. R. Putnam.... 

1895 

177 




305 



27 

E. Smith . 

1899 

178 





280 


64 

W. H. Burger. 

1910 

179 

149 






51 

G. R. Putnam.... 

1894 

178 



35 




85 

W. H. Burger. 

1909 

180 

146 





Tin . 


H. D. King. 

1910 

180 

152 






218 

J. F. Hayford _ 

1902 

185 







179 

J. D. Powell. 

1915 

184 

163 






112 

T. L. Warner. 

1911 

181 

156 






165 

C. L. Gamer. 

1915 

183 

170 






204 

J. D. Powell. 

1915 

185 

165 






135 

.do. 

1914 

182 

159 
















83 

H. D. King. 

1910 

180 

152 






59 

W. H. Burger. 

1909 

179 

147 





Pensacola, Fla. 

164 

C. L. Garner. 

1915 

183 

171 













































































































































































































190 


INDEX TO PUBLICATIONS 


Name of station 

No. of 
station 

Observer 

Year ob¬ 
served 

Descrip¬ 
tion, this 
publica¬ 
tion 

Abstract 

This 

publica¬ 

tion 

Report, 
1891, 
App. 15 

Report, 
1894, 
App. 1 

Report, 
1897, 
App. 6 

Report, 
1898-99, 
App. 4 





Page 

Page 

Page 

Page 

Page 

Page 

Philadelphia, Pa. 

24 

G. R. Putnam 

1894 

178 



33 



Pierre, S. Dak. 

118 

T. L. Warner 

1911 

181 

157 





Pikes Peak, Colo. 

43 

G. R. Putnam 

1894 

178 



36 



Pittsburg, Pa. 

211 


1915 

185 

165 





Pleasant Valley Junction, Utah. 

48 

G. R. Putnam 

1894 

178 



35 



Point Isabel, Tex. 

8 

W. H. Burger 

1909 

177 

145 





Poplar, Mont. 

192 

C. L. Garner 

1915 

184 

173 






124 

T. L. Warner 

1911 

181 

157 






87 

W. H. Burger 

1909 

180 

147 






107 

T. L. Warner 

1911 

181 

155 






176 

C. L. Garner 

1915 

184 

172 















25 

G. R. Putnam 

1894 

178 



33 




3 

W. H. Burger 

1909 

177 

145 






205 

C. L. Garner . 

1915 

185 

175 
















6 

W. H. Burger 

1909 

177 

145 






146 

J. D. Powell.. . 

1915 

182 

• 160 






128 

C. L. Gamer. 

1914 

181 

167 






82 

H. D. King 

1910 

180 

152 
















212 

C. L. Garner 

1915 

185 

175 






197 

J. D. Powell.. 

1915 

184 

164 






38 

G. R. Putnam.. 

1894 

178 



37 




49 

_do. 

1894 

178 



35 




54 

T. C. Mendenhall. 

1891 

179 


551-553 





78 

H. D. King _ 

1910 

179 

151 






56 

T. C. Mendenhall . 

1891 

179 


546-547 





53 

G. R. Putnam.... 

1899 

179 







158 

C. L. Gamer. 

1915 

183 

169 






178 

J. D. Powell. 

1915 

184 

163 






72 

W. H. Burger. 

1910 

179 

150 






109 

T. L. Warner. 

1911 

181 

155 






81 

H. D. King. 

1910 

180 

152 






111 

T. L. Warner. 

1911 

1S1 

156 






133 

C. L. Gamer. 

1914 

182 

168 

. 





138 

J. D. Powell. 

1914 

182 

159 
















105 

T. L. Warner. 

1911 

181 

155 






61 

W. H. Burger. 

1910 

179 

149 






35 

G. R. Putnam_ 

1894 

178 



37 




142 

J. D. Powell. 

1914 

182 

160 






159 

C. L. Gamer. 

1915 

183 

169 






189 

.do. 

1915 

184 

173 






177 

J. D. Powell. 

1915 

184 

163 






114 

T. L. Warner. 

1911 

181 

156 






213 

C. L. Garner. 

1915 

185 

176 






206 

.do. 

1915 

185 

175 






90 

H. D. King. 

1911 

180 

153 





Wallace, Kars. 

41 

G. R. Putnam_ 

1894 

178 



36 



Washington, D. C. (Bureau of Standards) 

84 

W. H. Burger. 

1910 

180 

151 





Washington, D. C. (Coast and and Geo- 

21 

G. R. Putnam_ 

1891 



563 




detic Survey). 










T)n 



1894 



.J 

30,32,33 









| 

34,37 



Do. 



1895 





303,305 ,1 









306,307 j[ 

Do. 


Edwin Smith. 

1899 









(1900 

177 





1 352-353 

Do. 


W. H. Burger. 

|l909 


146,148 




| app. 5, 










1901. 

Do. 



190S-9 


144 




Do. 



1910 


150.152 



. 1 . 
































































































































































































INDEX TO PUBLICATIONS, 


191 


Name of station 

No. of 
station 

Observer 

Year ob¬ 
served 

Descrip¬ 
tion, this 
publica¬ 
tion 

This 

publica¬ 

tion 

Report, 
1891, 
App. 15 

Abstract 

Report, 
1894, 
App. 1 

Report, 
1897, 
App. 6 

Report, 
1898-99, 
App. 4 





Page 

Page 

Page 

Page 

Page 

Page 

Washington, D. C. (Coast and Geodetic 


T. L. Warner. 

1911 


155 





Survey . 










Do. 



1912 


158 





Do. 


C. L. Garner. 

1914 


166,167 





Do. 



1915 


169,172 





Do. 



1916 


176 





Do. 


J. D. Powell 

1914 


158 





Do. 



1915 


160,162 





Do. 



1916 


166 





Washington, D. C. (Smithsonian Institu- 

22 

T. C. Mendenhall . 

1891 

177 






tion). 










Wasta, S. Dak... 

201 

C. L. Garner. 

1915 

184 

175 





Watertown, N. Y. 

132 

.. .do.. 

1914 

182 

168 





West Palm Beach, Fla. 

2 

W. H. Burger. 

1909 

177 

145 





Wheeling, W. Va. 

207 

J. D. Powell 

1915 

185 

165 





Whitehall, N. Y. 

130 

C. L. Garner. 

1914 

182 

168 





Wilmer, Ala. 

93 

H. D. King.. 

1911 

180 

153 





Wilmington, N.C. 

149 

J. D. Powell. 

1915 

182 

161 





Wi ! son, N. Y. 

88 

W. H. Burger. 

1909 

180 

147 





Winnemucca, Nev. 

115 

T. L. Warner. 

1911 

181 

156 





Winona, Minn. 

181 

J. D. Powell. 

1915 

1S4 

164 





Winston-Salem, N. C . 

154 

.do.. 

1915 

183 

161 





Worcester, Mass. 

28 

E. Smith. 

1899 

178 





279 


68 

W. H. Burger. 

1910 

179 

149 





Yuma, Ariz. 

65 

.do. 

1910 

179 

149 









































































































































































■ 











































































































GENERAL INDEX. 


Page. 


Abstracts of results of gravity observations. 139 

Analytical methods, depths of compensation and constants of the 

gravity formulas derived. 113 

Anomalies: 

And elevations, differences of, for sets of near stations. 94 

By Hay ford, Bouguer, and free-air reductions. 59 

Comparison of apparent, at stations in the United States by 

the Hayford and old methods of reduction. 58 

Gravity, for various depths of compensation for stations in the 

United States. 103 

Hayford, Bouguer, and free-air, arranged in groups according 

to topography. 63 

Hayford, for specified formations, United States stations. 71 

Hayford, for specified formations, United States stations, sum¬ 
mary of. 72 

Hayford, for various depths of compensation, arranged in 

groups accQrding to topography. 107 

Local and regional at— 

Eighteen coast stations. 88 

Thirty-nine stations in the interior and not in mountain¬ 
ous regions. 90 

Eighteen stations in mountainous regions and above the 

general level. 91 

Twenty-two stations in mountainous regions and below 

the general level. 90 

Twenty-five stations near the coast. 89 

Mean, for various depths of compensation based upon the 
United States Coast and Geodetic Survey formula for 1912.. 107 

Mean, Hayford, Bouguer, and free-air for all United States 

stations. 67 

Mean, Hayford, Bouguer, and free-air for various topographic 

groups. 67 

Of different magnitudes, number. 61 

On Cenezoic formations. 76 

On effusive formations. 77 

On intrusive formations. 77 

On Mesozoic formations. 75 

On Paleozoic formations. 74 

On pre-Cambrian formations. 72 

On unclassified formations. 77 

Relation between the gravity and the— 

Areas of erosion and deposition. 84 

Geologic formation at stations in Canada. 80 

Geologic formation at stations in India. 81 

Geologic formacion at stations in the United States. 70,71 

Geologic formation at stations in the United States not 

within 20 miles of another formation. 78 

Geologic formation shown graphically. 82 

Topography. 63 

Relation of local compensation and regional compensation to 

the topography. 88 

Summary of mean, for various depths of compensation and the 

various values of equatorial gravity. 106 

Anomaly maps, gravity, explanation. 61 

Areas deduced from gravity and from deflection data, agreement 

as to positive and negative. 62 

Assumptions made in regard to the topography and isostatic com¬ 
pensation. 8 

Attractions for various masses, table. 73 

Bibliography. 135 

Bouguer, Hayford, and free-air anomalies arranged in groups 

according to topography. 63 

Bouguer, Hayford, and free-air reductions, anomalies. 59 


Page. 


Canada: 

Relation between the gravity anomalies and the geologic 

formation at stations. 80 

Principal facts for 42 stations. 54 

Cenozoic formations: 

Anomalies. 76 

Canadian stations and Hayford anomalies. 80 

Hayford anomalies at stations, which are not within 20 miles 

of other formations. 79 

Indian stations and Hayford anomalies. 81 

United States stations and Hayford anomalies. 71 

Change of sign due to distance. 8 

Chronometer rates, comparison of, for stations near and distant 

from Washington. 143 

Coast: 

Hayford anomalies for various depths of compensation at 46 

stations near. 108 

Hayford, Bouguer, and free-air anomalies for 46 stations near.. 64 

Local and regional compensation anomalies at 25 stations near. 89 
Coast stations: 

Hayford anomalies for various depths of compensation at 27... 107 

Hayford, Bouguer, and free-air anomalies for 27. 63 

Local and regional compensation anomalies at 18. 88 

Coefficients of the gravity formula and depth of compensation, 

observation equations for obtaining. 115 

Comparison between local and regional isostatic compensation... 85 

Comparison of apparent anomalies at stations in the United States 

by the Hayford and old methods of reduction. 58 

Compensation: 

And topography, corrections for, and mean elevations for 

separate zones at selected stations in Europe. 45 

And topography, corrections for, and mean elevations for 

separate zones at stations in the United States. 19 

And topography, corrections for, for given depths of com¬ 
pensation . 100 

And topography for given depths of compensation, factors used 

in computing resultant of. 99 

Assumptions made in regard to the topography and. 8 

Uepth of, best. 112,133 

Depths of, and constants for the gravity formulas derived by 

analytical methods. 113 

Effect on the intensity of gravity of changes in the depth. 97 

For given depths of compensation, factors used in computing. 98 

Graphic determination of the most probable depth. Ill 

Gravity anomalies for various depths of, for stations in the 

United States. 103 

Hayford anomalies for various depths of, arranged in groups 

according to topography. 107 

Helmert’s depth of, from gravity observations. 131 

Mean anomalies for various depths of, based upon the United 

States Coast and Geodetic Survey formula for 1912. 107 

Observation equations for obtaining coefficients of the gravity 

formula and depth. 115 

Reduction tables for effect of topography and. 9 

Regional versus local distribution. 85 

Relation between the depth of, and the topography. 107 

Statement concerning the various solutions for obtaining 

depth. 130 

Summary of mean anomalies for various depths of, and the 

various values of equatorial gravity. 106 

Computation, explanation of methods of, and definition of terms.. 7 

Constants for the gravity formulas and depths of compensation 
derived by analytical methods. 113 


59387°—17-13 


193 



















































































194 


GENERAL INDEX, 


Page. 


Constants of the gravity formula and related quantities as derived 

from the various analytical solutions. 129 

Corrections and additions to reduction tables. 9 

Corrections for change of depth, station 195, Lander, Wyo. 99 

Corrections for topography and isostatic compensation and mean 

elevations for separate zones at selected stations in Europe. 45 

Corrections for topography and isostatic compensation and mean 
elevations for separate zones at stations in the United States.... 19 

Corrections for topography and isostatic compensation for given 
depths of compensation. 100 

Definition of terms and explanation of methods of computation.. 7 

Deflection and gravity data, agreement as to positive and negative 

areas deduced from. 62 

Deposition and erosion, relation between the gravity anomalies 

and areas. 84 

Depth of compensation: 

And coefficients of the gravity formula, observation equations 

for obtaining. 115 

And gravity formula, statement concerning the various solu¬ 
tions for obtaining. 130 

Best. 112,133 

Corrections for, station 195, Lander, Wyo. 99 

Effect on the intensity of gravity of changes in the. 97 

Graphic determination of the most probable. Ill 

Helmert’s, from gravity observations. 131 

Relation between the, and the topography. 107 

Depths of compensation: 

And constants for the gravity formula derived by analytical 

methods. 113 

Corrections for topography and isostatic compensation for 

given. 100 

Factors used in computing compensation for given. 98 

Factors used in computing the resultant of topography and 

compensation for given. 99 

Gravity anomalies for various, for stations in the United 

States. 103 

Hayford anomalies for various, arranged in groups according 

to topography. 107 

Mean anomalies for various, based upon the United States 

Coast and Geodetic Survey formula for 1912. 107 

Summary of mean anomalies for various, and the various val¬ 
ues of equatorial gravity. 106 

Descriptions of gravity stations. 177 

Distribution of compensation, regional versus local. 85 

Divided zones, reduction tables. 11 

Effusive formations: 

Anomalies. 77 

Hayford anomalies at stations on, which are not within 20 

miles of other formations. 79 

Indian stations and Hayford anomalies. 81 

United States stations and Hayford anomalies. 71 

Elevation of the station, effect of the, upon the intensity of gravity. 93 

Elevation, sets of adjacent stations having great differences. 93 

Elevations and anomalies, differences of, for sets of near stations.. 94 

Elevations, mean, and corrections for topography and isostatic 
compensation for separate zones at selected stations in Europe.. 45 

Elevations, mean, and corrections for topography and isostatic 
compensation for separate zones at stations in the United States. 19 
Equations, observation, for obtaining coefficients of the gravity 

formula and depth of compensation. 115 

Equatorial gravity, summary of mean anomalies for various depths 

of compensation and the various values. 106 

Erosion and deposition, relation between the gravity anomalies 

and areas. 84 

Europe, mean elevations and corrections for topography and iso¬ 
static compensation for separate zones at selected stations. 45 

Factors used in computing compensation for given depths of 

compensation. 98 

Factors used in computing the resultant of topography and com¬ 
pensation for given depths of compensation. 99 

Field, methods of observing used in the, and standardization of 

pendulums. 139 

Flattening, best value of, from all available gravity stations 
reduced for topography and isostatic compensation. 127,134 


Page. 


Formula: 

Best, from all available gravity stations reduced for topog¬ 
raphy and isostatic compensation. 127,134 

Constants of the gravity, and related quantities as derived 

from the various analytical solutions. 129 

For 1912, mean anomalies for various depths of compensation 
based upon the United States Coast and Geodetic Survey.. IS 

Gravity, Helmert’s, for 1901. 49 

Gravity, of 1912. 53 

Gravity, of 1916. 123,134 

Observation equations for obtaining coefficients of the gravity, 

and depth of compensation. 115 

Statement concerning the various analytical solutions for 

obtaining the gravity. 130 

Formulas, constants for the gravity, and depths of compensation 

derived by analytical methods. 113 

Free-air, Hayford and Bouguer anomalies arranged in groups 

according to topography. 63 

Free-air, Hayford and B ouguer reductions, anomalies. 59 

Geologic formation: 

Relation between the gravity anomalies and the— 

At s tations in Canada. 80 

At stations in India. 81 

At stations in the United States. 70,71 

At stations in the United States not within 20 miles of 

another formation. 78 

Shown graphically. 82 

Graphic determination of the most probable depth of compensa¬ 
tion. Ill 

Gravity: 

And deflection data, agreement as to positive and negative 

areas deduced from. 62 

Anomalies and the topography, relation between. 63 

Anomalies for various depths of compensation for stations in 

the United States. 103 

Anomalies, relation between the, and the— 

Areas of erosion and deposition. 84 

Geologic formation at stations in Canada. 80 

Geologic formation at stations in India. 81 

Geologic formation at stations in the United States. 70,71 

Geologic formation shown graphically. 82 

Anomaly maps, explanation. 61 

Effect of changes in the depth of compensation on the intensity 97 

Effect of the elevation of the station upon the intensity. 93 

Equatorial, summary of mean anomalies for various depths of 

compensation and the various values. 106 

Formula and depth of compensation, statement concerning 

the various solutions for obtaining. 130 

Formula, constants of the, and related quantities as derived 

from the various analytical solutions. 129 

Formula, observation equations for obtaining depth of com¬ 
pensation and coefficients of the. 115 

Formula of 1912. 53 

Formula of 1916. 123,134 

Formulas, constants for the, and depths of compensation 

derived by analytical methods. 113 

Observations, Helmert’s depth of comp tion from. 131 

Stations— 

Abstracts of observations. 144 

Descriptions. 177 

Names and numbers.50-57 

Hayford and old methods of reduction, comparison of apparent 

anomalies at stations in the United States by the. 58 

Hayford anomalies: 

For specified geologic formations— 

Canadian stations. 80 

Indian stations. 81 

United States stations. 71 

United States stations, summary. 72 

For stations in the United States on specified formations and 

not within 20 miles of other formations. 78 

For various depths of compensation arranged in groups ac¬ 
cording to topography. 107 

Hayford, Bouguer, and free-air anomalies arranged in groups ac¬ 
cording to topography. 63 
























































































GENERAL INDEX 




Page. 


Hayford, Bouguer, and free-air reductions, anomalies. 59 

Helmert’s depth of compensation from gravity observations. 131 

Helmert’s gravity formula of 1901. 49 

India, principal facts for 73 stations.55,56 

India, relation between the gravity anomalies and the geologic 

formation at stations. 81 

Interior and not in mountainous regions: 

Hayford anomalies for various depths of compensation at 87 

stations. 109 

Hayford, Bouguer, and free-air anomalies for 88 stations. 64 

Local and regional compensation anomalies at 39 stations.. 90 
Intrusive formations: 

Anomalies. 77 

Hayford anomalies at stations on, which are not within 20 

miles of other formations. 79 

United States stations and Hayford anomalies. 71 

Isostasy defined. 7 

Local and regional compensation anomalies: 

At 18 coast stations. 88 

At 18 stations in mountainous regions and above the general 

level. 91 

At 22 stations in mountainous regions and below the general 

level. 90 

At 39 stations in the interior and not in mountainous regions.. 90 

At 25 stations near the coast. 89 

Local-compensation anomalies and regional-compensation anoma¬ 
lies, relation to the topography. 88 

Local versus regional distribution of compensation. 84 

Maps, gravity anomaly, explanation. 61 

Masses, table of attractions for various. 73 

Mesozoic formations: 

Anomalies. 75 

Canadian stations and Hayford anomalies. 80 

Hayford anomalies at stations on, which are not within 20 

miles of other formations. 78 

Indian stations and Hayford anomalies. 81 

United States stations and Hayford anomalies. 71 

Methods of computation, explanation of, and definition of terms. 7 
Mountainous regions and above the general level: 

Hayford anomalies for various depths of compensation at 20 

stations. 108 

Hayford, Bouguer, and free-air anomalies for 20 stations. 66 

Local and regional compensation anomalies at 18 stations.... 91 

Mountainous regions and below the general level: 

Hayford anomalies for various depths of compensation at 36 

stations. 108 

Hayford, Bouguer, and free-air anomalies for 36 stations. 66 

Local and regional compensation anomalies at 22 stations.... 90 

Observation equations for obtaining coefficients of the gravity 

formula and depth of compensation. 115 

Observations and reductions, pendulum. 144 

Observing, methods of, used in the field and standardization of 
pendulums. 139 

Paleozoic formations: 

Anomalies. 74 

Canadian stations and Hayford anomalies. 80 

Hayford anomalies at stations on, which are not within 20 

miles of other formations. 78 

Indian stations and Hayford anomalies. 81 

United States stations and Hayford anomalies. 71 

Pendulum observations and reductions. 144 

Pendulums, standardization of, and methods of observing used 

in the field. 139 

Pendulums, summary of periods of, resulting from standardiza¬ 
tions at Washington base station. 141 

Pre-Cambrian formations: 

Anomalies. 72 

Canadian stations and Hayford anomalies. 80 

Hayford anomalies at stations on, which are not within 20 

miles of other formations. 78 

Indian stations and Hayford anomalies. 81 

United States stations and Hayford anomalies. 71 


195 

Page. 


Principal facts for: 

42 stations in Canada. 54 

73 stations in India. 55,56 

219 stations in the United States. 48,50 

40 stations not in the United States proper, Canada, or India.. 57 

Rates, comparison of chronometer, for stations near Washington 

and stations distant from Washington. 143 

Reductions: 

Comparison of the apparent anomalies at stations in the United 

States by the Hayford and old methods. 58 

Table, corrected, for zone C. 10 

Tables, corrections and additions. 9 

Tables for divided zones. 11 

Tables for effect of topography and isostatic compensation.... 9 

Reductions, anomalies by Hayford, Bouguer, and free air. 59 

Reductions, pendulum observations and. 144 

Regional and local compensation anomalies: 

At 18 coast stations. 88 

At 18 stations in mountainous regions and above the general 

level. 91 

At 22 stations in mountainous regions and below the general 

level. 90 

At 39 stations in the interior and not in mountainous regions.. 90 

At 25 stations near the coast. 89 

Relation to the topography. 88 

Regional versus local distribution of compensation. 85 

Relation between the depth of compensation and the topography. 107 

Relation between the gravity anomalies and the— 

Areas of erosion and deposition. 84 

Geologic formation at stations in Canada. 80 

Geologic formation at stations in India. 81 

Geologic formation at stations in the United States.70,71 

Geologic formation at stations in the United States not within 

20 miles of other formations. 78 

Geologic formation shown graphically. 82 

Topography. 63 

Relation of local and regional compensation anomalies to the 

topography. 88 

Results of gravity observations, abstracts. 139 

Sign, change of, due to distance. 8 

Standardization of pendulums and methods of observing used in 

the field. 139 

Standardization at Washington base station, summary of periods 

of pendulums resulting from. 141 

Stations, gravity: 

Abstracts of observations. 144 

Descriptions. 177 

Names and numbers.50-57 

Summary, Part 1. 133 

Summary of periods of pendulums resulting from standardizations 
at Washington base station. 141 

Table, corrected reduction, for zone C. 10 

Tables: 

Corrections and additions to reduction. 9 

Reduction, for divided zones. 11 

Reduction, for effect of topography and isostatic compensation. 9 

Terms, definition of, and explanation of methods of computation.. 7 

Topography and compensation for given depths, factors, used in 

computing resultant of. 99 

Topography and isostatic compensation: 

Assumptions made in regard to. 8 

Corrections for, and mean elevations for separate zones at 

selected stations in Europe. 45 

Corrections for, and mean elevations for separate zones at sta¬ 
tions in the United States. 19 

Corrections for, for given depths of compensation. 100 

Reduction tables for effect. 9 

Topography: 

Hayford anomalies for various depths of compensation 

arranged in groups according to. 107 

Hayford, Bouguer, and free-air anomalies arranged in groups 

according to. 63 

Relation between the depth of compensation and the. 107 

Relation between the gravity anomalies and the. 63 

Relation of the local and regional compensation anomalies to 
the. 88 
































































































196 


GENERAL INDEX. 


United States: Page. 

Comparison of apparent anomalies at stations in the, by the 

Hayford and old methods of reduction. 58 

Gravity anomalies for various depths of compensation for sta¬ 
tions in the. 103 

Mean elevations and corrections for topography and isostatic 

compensation for separate zones at stations in the. 19 

Principal facts for 219 stations in the.48,50 

Relation between the gravity anomalies and the geologic for¬ 
mation for stations in the.70,71 

Relation between the gravity anomalies and the geologic for¬ 
mation for stations in the, which are not within 20 miles of 
other formations 


United States—Continued. Page. 

Stations and Hayford anomalies for specified geologic forma¬ 
tions. 71 

Washington base station, summary of periods of pendulums result¬ 
ing from standardizations at. 141 

Washington, chronometer rates for stations near. 143 

Washington, chronometer rates for stations distant from. 143 

Zone C, corrected reduction table for. 10 

Zones, divided, reduction tables for. 11 


78 






















Fig. 10.—Map showing location of gravity stations in the United States and Canada used in this investigation. 








































































































































11 



Fig. 11.—Lines of equal anomaly in the United States and s6uthern Canada for the Hayford 1912 method of reduction (depth of 

COMPENSATION, 113.7 KILOMETERS.) 































































































































































12 



Fig. 12 . — Lines of equal anomaly in the United States for the Hayford 1916 method of reduction (depth of compensation. 60 kilometers). 





























































































































































































13 


125° 


120 ° 


115° 


110 ° 


105° 


100 * 


95 


90° 


85 


80° 


75° 


70° 


65 



45 


40 


35 


30° 


25 


Fig. 13.—Lines of equal anomaly in the United States for the Bouguer method of reduction. 





























































































































































































14 



Fig. 14.—Lines of equal anomaly in the United States for t^e free-air method of reduction. 






























































































































































































* 0 * 



Scale of Statute Miles 




L 




•0 0 10 20 30 40 50 

Fig 15. Enlarged scale for the region surrounding Washington. D. C., showing lines of equal anomaly for the Hayford 1912 method of reduction 

(DEPTH OF COMPENSATION. 113.7 KILOMETERS.) 


























































































16 ' 



I I I It 11 I I 11 


Scale of Statute Miles 

J_I 


J 


0 10 20 30 CO 50 

Fig. 16. Enlarged scale for the region surrounding Washington. D. C.. showing lines of equal anomaly for the Hayford 1916 method of reduction 

(DEPTH OF COMPENSATION. 60 KILOMETERS ) 

























































































17 


40 ‘ 


35° 



/ 


Fig. 17. —Geologic formations in the United States east of the Rocky Mountains. 














































































































































































RESIDUALS OF SOLUTION H 


All stations and areas ot excessive and defective density. 


O 190 
+.017 


+.021 


+. 02 *+ 


74^059; 


75 *051 


Co?- 1 " 


♦014 


40*.0I4 


,01 *° 29 
,02 *0° U 


Fig. 18. — Illustration from Supplementary Investigation in 1909 of the Figure of the Earth and Isostasy. showing residuals of Solution H, all stations, with areas of excessive and defective density, and showing also all gravity stations and the Hayford 1912 anomalies 




) 'nil 


S? \ * 1 ' 









































































































































































































































